POST UTME OSUSTECH 2020 Biology | Objective

Practice these randomly selected questions to test your readiness.

Question 1
In a desert e\cosystem, what is the primary adaptation of cacti to conserve water?
A. Thick, waxy stems to store water
B. Deep roots to access groundwater
C. Small leaves to reduce transpiration
D. Spines to reduce water loss through evaporation
Question 2
In a coral reef e\cosystem, what is the primary source of energy for the food web?
A. Phytoplankton
B. Zooplankton
C. Detritus
D. Fish
Question 3
A plant has a photosynthetic rate of 10 μmol CO2 s-1. If the light intensity is increased by a factor of 4, what is the new photosynthetic rate?
A. 20 μmol CO2 s-1
B. 40 μmol CO2 s-1
C. 80 μmol CO2 s-1
D. 160 μmol CO2 s-1
Question 4
A 2.5-liter solution contains 1.5 liters of ethanol and 0.5 liters of water. What is the mole \fraction of ethanol in the solution?
A. 0.6
B. 0.7
C. 0.8
D. 0.9
Question 5
In the context of genetics, what is the term for the process by which a gene is turned on or off?
A. Gene expression
B. Gene mutation
C. Gene regulation
D. Gene duplication
Question 6
A plant cell is placed in a solution with a high concentration of sucrose. What is the expected outcome?
A. The cell will shrink due to water loss
B. The cell will swell due to water uptake
C. The cell will remain unchanged
D. The cell will burst due to osmotic pressure
Question 7
In a population of 1000 individuals, 80% are susceptible to a disease, 15% are infected, and 5% are recovered. If the disease is transmitted through direct contact with an infected individual, and the probability of transmission is 0.2, what is the expected number of new infections in the next time period?
A. 180
B. 200
C. 220
D. 240
Question 8
The theory of evolution by natural selection was first proposed by Charles Darwin in his book 'On the Origin of Species'. Which of the following is a key concept of this theory?
A. Survival of the fittest
B. Natural selection
C. Speciation
D. Genetic drift
Question 9
A population of 1000 individuals has a birth rate of 0.02 and a death rate of 0.01. What is the expected rate of change of the population?
A. -0.01
B. 0.00
C. 0.01
D. 0.02
Question 10
In a grassland e\cosystem, what is the primary adaptation of grasses to survive drought?
A. Deep roots to access groundwater
B. Small leaves to reduce transpiration
C. Waxy stems to store water
D. Spines to reduce water loss through evaporation
Question 11
A diagram of the human eye is shown below. Identify the part labeled 'A' in the diagram.
A. Cornea
B. Iris
C. Lens
D. Retina
Question 12
A 5.0 L container is filled with 2.0 mol of an ideal gas at a temperature of 300 K. If the gas is heated to 400 K, what is the new volume of the gas?
A. 5.5 L
B. 6.0 L
C. 6.5 L
D. 7.0 L
Question 13
A researcher is studying the effects of a new medication on a population of patients. Which of the following statistical measures would be most appropriate for analyzing the data?
A. Mean
B. Median
C. Mode
D. S\tandard Deviation
Question 14
In a tropical rainforest e\cosystem, what is the primary mechanism by which nutrients are cycled from the dead plants and animals back to the living organisms?
A. Decomposition by fungi and bacteria
B. Nutrient uptake by plant roots
C. Nutrient release through leaf fall
D. Nutrient cycling through animal migration
Question 15
A 10-gram sample of a compound containing only carbon and hydrogen is analyzed by combustion. The amount of carbon dioxide produced is 4.5 grams, and the amount of water produced is 3.2 grams. What is the empirical formula of the compound?
A. C2H4
B. C3H6
C. C4H8
D. C5H10

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