find sample stemco questionsCompete with peers; compete with yourself.And Best Yourself!MathematiCo PrimaryMathematiCo SecondaryScienCo PrimaryChemico SecondaryPhysico SecondaryBioCo SecondaryMathematiCo Primary Junior Senior Junior Welcome to your MathematiCo Sample Questions for Primary Junior Level Name Email The picture below shows the StemCo City map. What is the length of the road from home to school? 650m 550m 450m 400m None You buy some groceries from a store. You spilled coffee on a bill: What is the price of 1 kilogram of tomato? $4 $6 $3 $12 None In minecraft, to create 1 fishing rod you need 3 sticks and 2 webs: You want to create fishing rods for you and 4 of your friends. How many sticks and webs do you need? 15 sticks and 10 webs 12 sticks and 8 webs 5 sticks and 5 webs 15 sticks and 15 webs None SpongeBob wants to cook 5 Crab's burgers. One meat patty for Crab's burger takes 10 minutes to cook. SpongeBob puts 5 patties on the kitchen stove. In how many minutes are the patties cooked? 50 minutes 5 minutes 15 minutes 10 minutes None You enter a restaurant and see the following text on the transparent door: How does this text look from the inside of the restaurant? None Was it fun? Yes, it was. I want more... Please fill in the comment box below. Congratulation for finishing the test! Time's upSenior Welcome to your MathematiCo Sample Questions for Primary Senior Level Name Email 1. The picture below shows a set of blocks: How many cubical blocks are needed to complete this cuboid? Deselect Answer A. 12 B. 16 C. 20 D. 24 None 2. In a large bag of M&Ms 30% are brown candies and 18% are yellow candies. Your friend ate all the brown candies. You counted 63 yellow candies and ate them all. How many candies are left in the bag? Deselect Answer A. 105 B. 182 C. 168 D. 156 None 3. The distance between Athens and Ohrid is 420 km. Two cars left from Athens to Ohrid at the same time. One car is 10 km/h faster than the other car. The first car reached Ohrid one hour earlier than the second car. What was the speed of the second car? Deselect Answer A. 60 km/h B. 70 km/h C. 50 km/h D. 80 km/h None 4. The concept of average is important when analyzing large sets of data. For example: a) What is the most common height in your class? b) Who is taller on average, girls or boys, in your classroom? c) If you arrange your classmates in order of increasing height, how tall is the person in the middle? All these questions require the consideration of average values. However, each of these questions asks a different kind of average. What is the correct matching between the questions and the type of average? Deselect Answer A. 1 - mode, 2 - mean, 3 - median B. 1 - mean, 2 - mode, 3 - median C. 1 - median, 2 - mode, 3 - mean D. 1 - mode, 2 - median, 3 - mean None 5. What is the total number of stars in Figure 6? Deselect Answer A. 300 - 350 B. 350 - 400 C. 400 - 450 D. 450 - 500 None Time's upMathematiCo SecondaryJunior Senior Junior Welcome to your MathematiCo Sample Questions for Secondary Junior Level Name Email 1. In one of his books, Isaac Asimov described the communication between a human and an alien. Imagine that you are in the place of this person and you know the following principles of the aliens’ mathematics: You want to explain to him explain how gravity acceleration works on your planet by describing thefollowing formula in their Math language:S = vt + 4.9t2How will this formula look in the mathematical language of the alien?Deselect Answer A. v↞t↺(4.9↝t↨0) B. (v↝t↨4.9) ↞t↺v C. 9.8↝t↨(v↞5↺v D. t↞v↺(9.8↝t↨2) None 2. The most efficient way to pack many spheres into a given volume is to use a regular, hexagonal lattice. This fact has been ‘known’ to us for thousands of years, yet it was only mathematically proven in 1998 by Thomas Hales. It has many profound implications on our daily lives, from stacks of groceries and cannonballs, to the atoms in a crystal. Let us consider the simpler 2D case. Those who play pool, will know that the most efficient wayto “squeeze” circles into a given area is to use hexagonal packing, as shown belowPacking efficiency is defined as how efficiently the space is used, i.e. the area of the circles dividedby the total area used (including ‘between’ circles). If the 2D hexagonal packing is extendedinfinitely, what is the packing efficiency?Deselect Answer A. 80% to 85% B. 85% to 90% C. 90% to 93% D. 93% to 95% None 3. The Chicken McNugget Theorem was discovered when people realised certain numbers of nuggets could not be bought from a fast-food restaurant. As nuggets could only be purchased in groups of 9 and 20, certain numbers of nuggets, such as 7 and 28, cannot be purchased. The greatest number of items that cannot be purchased is given by the formulamn – m – nif the items can only be purchased in groups of m and n.Hence, the greatest number of nuggets that cannot be purchased is:9(20) – 9 – 20 = 151 nuggets. Any larger number of nuggets can be purchased. For example, 152nuggets can be purchased in 4 bags of 20 and 8 bags of 9, and 153 nuggets can be purchased in17 bags of 9.Another restaurant sells chicken wings in boxes of 7 and 16. What is the greatest number of chickenwings that cannot be bought?Deselect Answer A. 23 B. 82 C. 89 D. 111 None 4. A tour group consisting of one family of three, two couples, and three individual travellers are visiting Chatou in France and need to stay in a hotel for the night. What is the minimum cost required to house the travellers, given that the family of three must stay inone room, and each couple must not be sharing their room with another person?Deselect Answer A. $600 B. $470 C. $730 D. $520 None 5. A knight in chess moves in a L-shaped pattern as shown below: The white knight can move to any square with a white dot, and the black knight can move to anysquare with a black dot. What is the minimum number of moves needed for a knight to move from the red square to thegreen square?Deselect Answer A. 3 B. 4 C. 5 D. 6 None Time's upSenior Welcome to your MathematiCo Sample Questions for Secondary Senior Level Name Email 1. Shown below is Google’s COVID-19 data as of November 2020 Which of the following conclusions is the most false?Deselect Answer A. Italy has over one million cases in total B. There are fewer than 100,000 new cases per day in the United States C. The number of new cases have been decreasing in India over the last two months D. The number of new cases is increasing worldwide None 2. An astronomer observing a newly discovered star notices that it dims for 21 seconds, then brightens for 15 seconds, then dims again for 21 seconds, and so on periodically. The dimming / brightening pattern After 199 minutes, how many times has the star brightened after dimming?Deselect Answer A. 119 B. 109 C. 129 D. 99 None 3. Engineers in Space X are experimenting with a new system of navigation based on the 3D system of coordinates (x, y, z) with one unit equal to 10 00 km. In this system of coordinates (0, 0, 0) is the Earth. Logblock (flight log) of the satellite has the following records: How far is the satellite at the end of the fourth day?Deselect Answer A. 225 600 km B. 104 400 km C. 360 000 km D. 60 000 km None 4. For a positive integer n, we write ?(n) to say how many positive divisors n has.For example, because 6 has four divisors, which are 1, 2, 3, and 6, we have ?(6) = 4.Three positive integers a, b, c are given such that the sum ?(a) + ?(b) + ?(c) is an even number. What is the smallest possible value of a + b + c ?Deselect Answer A. 2 B. 3 C. 4 D. 5 None 5. In a game show, the contestant is asked to take out some balls out of a jar without looking. If he/she takes at least 19 balls of the same color, then he/she wins $20 000. However, taking each ball comes with a cost of $10. For example, if the contestant takes 19 balls and, being extremely lucky, the 19 balls are all the same color, then he/she wins $20000 but has to pay $190 for the balls, netting him/her $19 810 It is known that the jar contains exactly 100 golden balls and 100 silver balls. The contestantwants to be absolutely sure that he/she gets at least 19 balls of the same color, but doesn’t wantto pay too much for the balls.What is the smallest number of balls that the contestant should take?Deselect Answer A. 13 B. 19 C. 37 D. 51 None Time's upScienCo PrimaryJuniorSeniorJunior Welcome to your ScienCo Sample Questions for Primary Junior Level Name Email 1. Animals are classified into families. The Felidae family is a group of animals that look like cats. Every animal from Felidae family has: ● Sharp teeth● Long tail● Hair coat● Four pawsWhich animal is from the Felidae family?Deselect Answer None 1 out of 5 2. Plants need water to grow. Which part of the plant absorbs the water?Deselect Answer A. Leaf B. Flower C. Stem D. Root None 2 out of 5 3. There are different time zones. London is 5 hours ahead of New York. Abu-Dhabi is 3 hours ahead of London. Moscow is 1 hour behind Abu-Dhabi. For example: ● When it is 6 PM in London, it is 1 PM in New York.● When it is 11 AM in Abu-Dhabi, it is 10 AM in Moscow.It is 4 PM in Moscow. What time is it in New-York?Deselect Answer A. 9 AM B. 11 PM C. 10 AM D. 6 PM None 3 out of 5 4. Water bails at 100 °C. Oil at 47 °C, alcohol at 78 °C. Sugar at 145 °C You heat 4 cups. The lower the boiling point, the earlier it starts to boil. Cups contain water, oil, alcohol or sugar. Which cup boils second?Deselect Answer A. Cup of water B. Cup of oil C. Cup of alcohol D. Cup of sugar None 4 out of 5 5. We all love fizzy drinks. However, we do not think much about the sugar in the drinks The table shows how much sugar is in a bottle of a drink.Which drink is the most sweet?Deselect Answer A. Coca-cola B. Pepsi C. Fanta D. Lipton None 5 out of 5 Time's upSenior Welcome to your ScienCo Sample Questions for Primary Senior Level Name Email 1. Biologists often use charts called dichotomous keys to identify different types of organisms. To use a dichotomous key, choose the characteristic that best matches the organism you are trying to identify. Continue doing so until the species is identified. Bobby’s family recently adopted this dog, and he is curious to find out what breed it isUsing the dichotomous key, what breed of dog is this most likely to be?Deselect Answer A. Terrier B. Poodle C. Dachshund D. Bearded Collie None 2. Have you wondered how temperature changes with altitude? For example, at the cruising altitude of most jet aircrafts (between 9,000 and 12,000 m) the air temperature ranges from -40 °C to -57 °C. It can be approximated that every 100 m going up, the air temperature drops by about 1 °C. A group of tourists start its hike at the bottom of the Alatau mountain on a sunny day, when the temperature is 32 °C. At what altitude are tourists expected to face the snow?Deselect Answer A. 1 000 m - 2 000 m B. 2 000 m - 3 000 m C. 3 000 m - 4 000 m D. 4 000 m - 5 000 m None 3. Phototropism combines the Greek photo, or "light," and tropism, "a turning". Put together the term phototropism refers to the movement of organisms towards light. In plants, phototropism helps to get the maximum amount of available energy by turning and growing in the sun’s direction. Auxin is the plant hormone that is responsible for phototropism. This hormone is concentrated in the head of the stem. Some students want to check the action of the auxin and put caps on the head of the stems. First cap is transparent (transmits the light), the second cap is opaque (does not transmit the light). Which of the following diagrams best reflects the observations that will be made after a couple ofdays?Deselect Answer None An electromagnet can be made by coiling a wire around an iron object such as a nail, and then connecting the wire to a battery. Electromagnets are commonly found in everyday items, such as fans and speakers. You can learn how to make a simple electromagnet by watching the video below: <a href=" />The greater the number of coils around the nail, the stronger the electromagnet will be. Bob sets upan experiment to investigate the relationship between the number of coils and the maximum weightthe electromagnet can lift. His results are shown below: Bob wants to lift even heavier objects with his electromagnet, and decides to build an electromagnetwith 100 coils. Can you estimate the maximum mass that can be lifted by this electromagnet?Deselect Answer A. 50 g B. 60 g C. 70 g D. 75 g None 5. You are playing angry birds. Your goal is to send the bird as far as you can: Which trajectory is the best option for your goal?Deselect Answer None Time's upChemico SecondaryJuniorSeniorJunior Welcome to your ChemiCo Sample Questions for Secondary Junior 1. Untreated car exhaust waste can contain pollutants such as toxic carbon monoxide gas, cancerous hydrocarbons, and nitrogen oxides which cause smog. In order to address this problem, most cars have catalytic converters installed which convert carbon monoxide into carbon dioxide, hydrocarbons into carbon dioxide and water, and nitrogen oxides to nitrogen gas and oxygen gas. A sample of car exhaust was analysed before and after a catalytic converter was installed toprocess the exhaust gas.The concentration of which of the following gases will have decreased in the exhaust after thecatalytic converter is installed?Deselect Answer A. CO B. CO2 C. H2O D. N2 None 1 out of 5 2. A fire is a terrible destructive event, but what is even more damaging is the automatic water irrigation systems. Museum exhibits or electronics in a hardware store will suffer from water even if they are not burned by fire, so a different fire extinguishing system is used in such places: 1) People leave the room2) The room is completely sealed off by the system3) Pumps fill the room with argon and thereby reduce the concentration of oxygen in the roombelow the minimal 15% required to sustain burning.Imagine a fire started in an art hall with a width of 10 m, a length of 15 m, and a height of 4 m. Theinitial concentration of oxygen in the air is 20%. The fire extinguishing system pumps 100 m3 ofargon every minute. The oxygen consumption and carbon dioxide production are insignificant,assuming the fire is detected and stopped right awayIn how many minutes will the system eliminate the fire in this room?Deselect Answer A. 4 B. 8 C. 6 D. 2 None 2 out of 5 3. Relative atomic mass of any element is based on the mass of its atoms. In the periodic table Deselect Answer A. 4 amu B. 37 amu C. 50 amu D. 61 amu None 3 out of 5 4. VSEPR theory is a theory of repulsion that describes the geometry of the molecule. According to that theory, molecules take a shape, which has the minimum repulsion between outer shell electrons (bonds). In other words, the bonds try to be as far away from each other as geometrically possible. In VSEPR, single and double bonds are considered equivalent in terms of repulsions.For the cysteine molecule below What are approximate bond angles x and y?Deselect Answer A. x = 90°; y = 90° B. x = 120°; y = 109° C. x = 120°; y = 90° D. x = 90°; y = 109° None 4 out of 5 5. Nixtamalization refers to the process of treating maize before it is ground into flour, in order to remove mycotoxins and to increase the nutritional value of the maize. In nixtamalization, maize is cooked and soaked in an alkaline (basic) solution. In the Americas, where maize has been a staple food for thousands of years, nixtamalization can betraditionally conducted as such: A special type of rock is heated to high temperatures, before beingadded to water. Maize is soaked and boiled in this water, before it is ground into flour.What could be the main constituent of this special rock?Deselect Answer None 5 out of 5 Time's upSenior Welcome to your Sample Questions for ChemiCo Secondary senior Level Name Email 1. Calorimetry is an experimental method to determine the enthalpy of reactions in an isolated system. A reaction is allowed to react in a calorimeter (an example is shown below) and the heat released is transferred to the water and the change in the temperature of the water measured is then used to calculate the enthalpy of the reaction using the formula Which one of the following scenarios would result in an overestimation of the enthalpy of thereaction?Deselect Answer A. The insulating jacket is faulty and allows heat transfer B. Not all reactants have reacted C. Using lukewarm water (40 °C) in the calorimeter instead of room temperature water (25 °C) D. The recorded value of the mass of the reactants is less than it actually is None 2. Electrolysis is a good method of covering rings with gold, silver and other expensive metals. In this process, the ring acts as a cathode and metal atoms in the solution evenly cover the ring. "StemGold" jewelry wants to try this method and cover a ring with silver. The ring has a 20 mm innerdiameter and a 21 mm outer diameter. In order to prepare the solution, the jeweler used 20 gramsof Electrolysis stopped after all of the silver was deposited onto the ring. Density of silver is Sizes of the ring are provided in the picture below.What is the new inner diameter of the ring after the electroplating process?Deselect Answer A. 14.00-14.99 mm B. 15.00-15.99 mm C. 16.00-16.99 mm D. 17.00-17.99 mm None 3. Pesticides are important compounds that are used for protection of crops from insects and microorganisms. Usage of pesticides highly increases crop production, but at the same time may result in food toxicity. In order to ban or approve pesticides, the United States Environmental Protection Agency (EAP) does research and evaluates the risks. EPA tests compounds on the rats and mice and evaluates the LD50 value - amount of substance per kilogram body weight required to lead to the lethal consequences of 50% of the test animals. LD50 value for artrazine (frequently used pesticide) is 1-4 g/kg depending on the animal species, that is why artrazine remains unbanned The table below represents LD50 values of different compounds for mice:Which compound is the most dangerous based on the LD50 value?Deselect Answer A. Batrachotoxin B. White phosphorus C. Ascorbic Acid D. Ibuprofen None 4. Hypercalciuria refers to high concentration of calcium ions present in the urine. This is a risk factor for the formation of kidney stones when insoluble calcium salts become supersaturated in the urine. To treat kidney stones, it is proposed to use chelating agents to reduce the concentration of free calcium ions in the urine and thereby reducing the saturation. Chelating agents are typically molecules or ions which are capable of forming multiple dative bonds with the metal cation. Which of the following substances is most likely able to prevent the formation of calcium stones inthe urine?Deselect Answer None 5. Organic chemistry has its roots in the mid 1700s, when thousands of alchemists around the world were experimenting with chemical compounds. Alchemists divided Chemistry into two main parts - "Inorganic Chemistry" and "Organic Chemistry". They believed that the two Chemistries do not have anything in common and have different principles from one another. In order to prove that theory, "vital force" ("live force") rules were developed: Chemical compounds coming from animals or plants are strongly connected to the soul and do not obey rules of inorganic chemistry.It may sound strange, but this theory was accepted by the vast majority of alchemists at the time.Which of the suggested reactions below is the most impossible according to the "vital force" theory?Deselect Answer A. Ammonium Cyanate → Urea B. Glycerine + Fatty Acid → Animal Fat C. Sodium + Chlorine → Sodium Chloride D. Hydrogen Chloride + Potassium → Potassium Chloride + Hydrogen None Time's upPhysico SecondaryJuniorSeniorJunior Welcome to your PhysiCo Sample Questions for Secondary Junior Level 1. The ammeter is a device used to measure the amount of current flowing in a system. This is done by allowing the current in the system to flow through the device. Another device used in electrical systems is the voltmeter. The voltmeter measures the potentialdifference between two points of the electrical system by diverting the electrical current away fromthe device to the rest of the circuit.The relationship between potential difference (V), current (I) and resistance (R) are as follows: V = IRWhich of the following properties of ammeters and voltmeters are compatible with their functions?Deselect Answer A. Ammeter: negligible resistance, Voltmeter: high resistance B. Ammeter: negligible resistance, Voltmeter: negligible resistance C. Ammeter: high resistance, Voltmeter: negligible resistance D. Ammeter: high resistance, Voltmeter: high resistance None 2. Newton's first law states that an object at rest will stay at rest, and an object in motion will stay in motion unless acted on by a net external force. Mathematically, this is equivalent to say that if the net force acting on an object is zero, then the velocity of the object is constant. When the bus starts to move abruptly, passengers lean back. In case of sudden braking, on the contrary, they lean forward. This observation seems to contradict Newton's first law, because outside forces do not act on thepeople. Which of the following is the correct statement regarding this observation?Deselect Answer A. Passengers move due to inertia in the direction of the bus’s original movement B. This is contrary to Newton's law and is an exception C. This phenomenon has nothing to do with forces and Newton’s law does not apply here. D. People lean voluntarily by exerting force to counteract the bus's movement. None 3. A hydraulic jack lift can be used to increase the force of an operator due to the difference in area of the pistons in the cylinders. The diagram below shows a modified hydraulic jack lift that has a cone shaped piston on the lifting edge. What utility can this modification provide for the hydraulic jack?Deselect Answer A. Increase of the upward distance travelled by the car for the same force applied by the operator B. Reduces the force required to lift the car up C. Reduces energy loss due to fluid drag D. No utility None Time's upSenior Welcome to your PhysiCo Sample Questions for Secondary Senior Level Name Email 1. A violin is a musical instrument, which produces notes of specific pitch (frequency) using the vibration of a metal string. The violinist controls the pitch by pressing a finger down on the string, which effectively changes the length of the vibrating string. The “A” string on a violin is roughly 330 mm long, and, when released completely, produces afrequency of 440 Hz. Given that the note D is 587.3 Hz, what is the distance between the bridge andthe finger at the note D?Deselect Answer A. 210 to 230 mm B. 230 to 250 mm C. 250 to 280 mm D. 280 to 310 mm None 2. The maglev train is a special type of high-speed train, which uses electromagnets to levitate the train over the tracks. Thanks to the complete lack of friction, maglev trains are able to achieve very high speeds. Let us study how the train levitates. There are permanent magnets on the bottom of the train, andelectromagnets on the tracks. By providing power to the electromagnets, they generate a magneticfield, thus repelling the permanent magnets and applying an upwards force on the train. Becausethe magnetic field is stronger at shorter distances, for the same amount of power, the repulsionis stronger when the train is lower, and weaker when the train is higher.Imagine a train that is levitating; the power of the electromagnets is perfectly tuned, so that the trainis hovering stationarily at a specific height. Suddenly, the power is decreased by a very smallamount.What happens?Deselect Answer A. The train will initially accelerate downwards, and then oscillate around a lower height B. The train will continuously accelerate downwards. C. The train will initially accelerate downwards, and then oscillate around the original height. D. The train will immediately move downwards at constant speed. None 3. A ball with mass m is thrown into a basket, at a distance L away. What is the minimum amount of kinetic energy needed to achieve this?Deselect Answer A. mgL B. 2 mgL D. 0 None 4. 4. Diffusion at higher temperatures is faster. This means that the speed of movement of molecules and temperature are related. When the temperature rises, the speed of movement of the molecules increases; when the temperature is low, it decreases. Consequently, the body temperature depends on the speed of movement of the molecules.Fig 1.0 is the graph of temperature against time.What of the following is correct?Deselect Answer A. Molecules and their movement are dependent on time B. Graph rises because temperature is rising C. Temperature increases because someone increases them D. When the temperature rises, the speed of movement of the molecules increases None Time's upBioCo SecondaryJuniorSeniorJunior Welcome to your BioCo Sample Questions for Secondary Junior Level Name Email 1. The Punnett square is an effective tool which can be used to predict the probability of different phenotypes arising from the breeding between two parental organisms. Consider the following example. Let there be a gene which has alleles dominant for blue eyes (B) and recessive for brown eyes (b). If a person with Bb genotype mates with another person with Bb phenotype, based on the Punnett square: There will be a 75% chance the offspring has blue eyes (25% BB, 50% Bb) and 25% chance theoffspring has brown eyes (bb).People with albinism have pink eyes and this masks the original color the person should haveinherited from the parents. Let the alleles for albinism be A and a and note that albinism is arecessive disorder (only people with the aa genotype will be albino).Shown below is a Punnett square for the possible genotypes of offspring of parents with the BbAa(blue eyed without albinism) and Bbaa genotypes (albino):In the scenario above, what are the chances that an offspring will have brown eyes?Deselect Answer A. 0.0% B. 12.5% C. 25.0% D. 50.0% None 2. Antibiotics are medicines used to fight bacteria. Traditional antibiotics prevent the formation of peptidoglycan which is required to create bacterial cell walls. As a result, bacteria burst because of the weakened cell wall and eventually die. Sometimes, people use antibiotics without a receipt of the doctor to fight a viral disease. However, antibiotics do not have any effect on viral disease development. Why are antibiotics not effective in fighting against the virus?Deselect Answer A. Viruses do not use peptidoglycan as a part of their structure B. Viruses do not have an envelope C. Viruses are not prokaryotes or eukaryotes D. Viruses have a much more complex shape None 3. Phylogeny is the diagram representing differences and similarities between different animal species. The less the length of the path between animals, the closer are the animal species. For example: Leopard and Domestic cat are closer to each other than Leopard and Wolf in terms of genetic similarities. For the phylogeny below, which pair of animal species is the farthest in terms of genetic similarities?Deselect Answer A. Sea bass and Bald eagle B. Sea bass and Alligator C. Sea bass and Lamprey D. Sea bass and Antelope None 4. Most plants produce glucose from carbon dioxide using the Calvin cycle. Three molecules of carbon dioxide are added to three molecules of RuBP, forming six molecules of3-PGA. These six molecules of 3-PGA are converted to six molecules of G3P. Five molecules ofG3P are used to regenerate the three molecules of RuBP, and one molecule of G3P is produced asan excess, and is eventually converted to glucose. One molecule of glucose requires two moleculesof G3P to produce.Some plants have an adaptation which allows them to store carbon dioxide as another molecule,oxalate. One molecule of oxalate can be converted back to two molecules of carbon dioxide.How many molecules of oxalate are needed to form one molecule of glucose?Deselect Answer A. 1 B. 2 C. 3 D. 4 None 5. Many decoration statues and sculptures are made of marble, a rock consisting of calcium carbonate, CaCO3 . In recent years, many statues placed outdoors experienced heavy damage. Calcium carbonate enters into reaction with sulfuric acid and gets dissolved: CaCO3 (insoluble solid) + H2SO4 (aqueous solution) → CaSO4 (aqueous solution) + H2O (liquid) + CO2 (gas)H2SO4 is formed by water, H2O, and sulfur trioxide, SO3 (H2O + SO3 → H2SO4). However, sulfurtrioxide is not a usual component of the atmosphere. What can explain its unexpected occurrence innature?Deselect Answer A. Temperature rise B. Industrial pollution C. Sulfur mining D. Soil erosion None Time's upSenior Welcome to your BioCo Sample Questions for Secondary Senior Level Name Email 1. Kary Mullis was an American biochemist who won the Nobel Prize in Chemistry in 1993 for his invention of the polymerase chain reaction technique (PCR). PCR allows for rapid amplification of DNA sequences which are important in many medical diagnostics to identify disorders, bacteria and viruses. For example, in the COVID-19 pandemic, PCR plays an essential role in helping to detect if a person carries the coronavirus. To amplify the DNA sequences using PCR, RNA primers are required. When designing RNA primers for PCR, one must take note to avoid the possibility of formation of hairpin loops of the RNA primers. Hairpin loops are formed when the bases in the RNA primer sequences are complementary and bind with itself, forming a hairpin-shaped loop Which of the following RNA primers can be used in PCR?Deselect Answer A. 5’-GGUUACGGGGUAACC-3’ B. 5’-ACGUACAGAGUACGU-3’ C. 5’-AAAAACCGCGUUUUU-3’ D. 5’-AUAAAUAGAGCCGGA-3 None 2. Scientists tested the action of two antibiotics on the population of bacterias. They put two drops of antibiotics into the petri dish and left it for 24 hours. After that experiment, two antibiotics showed the following results: Scientists are aimed to find a bacteria that has resistance against antibiotics. In which region dothose bacteria exist?Deselect Answer A. A B. B C. C D. D None 3. The diagram below shows the cardiac cycle of human: In which region, does oxygenated blood flow?Deselect Answer A. A B. B C. C D. D None 4. The diagram below represents light-dependent (on the left) and light-independent on the right) reactions of the photosynthesis: The plant was not receiving the sun rays for 3 days. Do light-independent reactions still occur in thatplant and why?Deselect Answer A. No, because it requires ATP and NADPH that comes from the light-independent reactions B. No, because it requires sun rays C. Yes, because it requires CO2 , which is still coming to the plant D. Yes, because it may replace ATP with ADP None 5. Greenhouse effect is the natural process that warms the Earth’s surface. Sun rays reach the surface and reflect. Some of it is reflected back to space and the rest is absorbed and re-radiated by greenhouse gases. The absorbed energy warms the atmosphere and the surface of the Earth. In the last three centuries, the amount of greenhouse gasses in the atmosphere dramaticallyincreased, which led to the increasing average temperature on the Earth and melting glaciers. Thediagram below represents the changes of the amount of greenhouse gasses with a pass of time:Which factor mostly affected the greenhouse effect situation in the 21st century?Deselect Answer A. Using oil as a fuel B. High volcanic activity C. Plastic waste D. Air pollution from factory waste None Time's up
