Practice post utme achievers university biology 2020 Past Questions

Question 1

In a typical xylem vessel, what is the primary function of the lignin component?

Correct A. To provide structural support to the vessel

B. To facilitate the transport of water and minerals

C. To regulate the rate of transpiration

D. To absorb excess water from the soil

Correct Answer: A

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Question 2

A population of rabbits in a forest is observed to have a birth rate of 0.05 per individual per year and a death rate of 0.01 per individual per year. Assuming a cons\tant population size, what is the carrying capacity of the forest?

A. 100

B. 200

C. 500

Correct D. 1000

Correct Answer: D

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Question 3

A geneticist is studying the inheri\tance of a particular trait in a population of pea plants. The trait is controlled by a \single gene with two alleles: R (dominant) and r (recessive). If a plant has the genotype Rr, what is the probability that it will express the dominant trait?

A. 0.5

Correct B. 0.75

C. 0.25

D. 0.33

Correct Answer: B

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Question 4

A microorganism is isolated from a patient's blood sample and identified as Staphylococcus aureus. The organism is found to be resis\tant to penicillin. What is the most likely mechanism of resis\tance?

Correct A. Beta-lactamase production

B. Efflux pumps

C. Target modification

D. Outer membrane porin loss

Correct Answer: A

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Question 5

A bio\logist is studying the classification of living organisms. Which of the following kingdoms is characterized by the presence of true branching and vascular tissues?

A. Animalia

Correct B. Plantae

C. Fungi

D. Protista

Correct Answer: B

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Question 6

In a population of Drosophila melanogaster, the frequency of the recessive allele 'a' is 0.2. If the population is in Hardy-Weinberg equilibrium, what is the frequency of the homozygous dominant genotype 'AA'?

Correct A. 0.36

B. 0.64

C. 0.72

D. 0.84

Correct Answer: A

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Question 7

A plant with the genotype 'Rr' is crossed with a plant with the genotype 'RR'. What is the probability that the offspring will have the genotype 'Rr'?

A. 0.25

Correct B. 0.5

C. 0.75

D. 0.9

Correct Answer: B

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Question 8

A solution of 0.1 M NaCl is diluted to 0.01 M. What is the new concentration of Na+ ions?

A. 0.001 M

Correct B. 0.01 M

C. 0.1 M

D. 1 M

Correct Answer: B

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Question 9

The xylem sap of a plant contains 0.5 M glu\cose. If the plant is watered with 0.1 M glu\cose solution, what is the new concentration of glu\cose in the xylem sap?

A. 0.3 M

B. 0.4 M

Correct C. 0.5 M

D. 0.6 M

Correct Answer: C

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Question 10

A 1 L solution of 0.1 M NaCl is diluted to 5 L. What is the new concentration of Na+ ions?

A. 0.002 M

Correct B. 0.01 M

C. 0.02 M

D. 0.05 M

Correct Answer: B

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Question 11

In a tropical rainforest e\cosystem, what is the primary mechanism by which plants obtain essential nutrients?

Correct A. Decomposition and nutrient cycling

B. Photosynthesis and transpiration

C. Nutrient uptake through roots

D. Nutrient fixation by microorganisms

Correct Answer: A

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Question 12

A species of bird has a unique mating ritual where the male performs a complex courtship display to attract a female. What is the primary purpose of this display?

A. To establish dominance over other males

Correct B. To demonstrate genetic fitness to the female

C. To signal the availability of food resources

D. To warn potential predators of the presence of the bird

Correct Answer: B

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Question 13

In a desert e\cosystem, what is the primary mechanism by which plants conserve water?

A. Transpiration and stomatal closure

B. Photosynthesis and water storage

C. Nutrient uptake through roots and water conservation

Correct D. CAM photosynthesis and crassulacean acid metabolism

Correct Answer: D

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Question 14

A species of fish has a unique reproductive strategy where the male fertilizes the eggs externally. What is the primary advantage of this strategy?

A. Increased genetic diversity

Correct B. Reduced parental investment

C. Improved egg survival rates

D. Enhanced mate choice

Correct Answer: B

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Question 15

In a coral reef e\cosystem, what is the primary mechanism by which coral polyps obtain essential nutrients?

A. Photosynthesis and transpiration

B. Nutrient uptake through tentacles

Correct C. Symbiotic relationship with zooxanthellae

D. Decomposition and nutrient cycling

Correct Answer: C

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Question 16

In a population of E. coli bacteria, the frequency of a particular mutation is 0.05. If the population size is 10^6, how many bacteria are expected to have the mutation?

Correct A. 500

B. 5000

C. 50,000

D. 500,000

Correct Answer: A

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Question 17

A plant has a genotype of BBSS for a particular gene. If the plant is crossed with a plant having the genotype bbss, what is the probability that the offspring will have the genotype BbSS?

A. 0.25

Correct B. 0.5

C. 0.75

D. 0.9

Correct Answer: B

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Question 18

A person has a blood type of AB and a Rh factor of positive. If the person's mother has a blood type of A and a Rh factor of negative, and the person's father has a blood type of B and a Rh factor of positive, what is the probability that the person's offspring will have a blood type of AB and a Rh factor of positive?

A. 0.25

Correct B. 0.5

C. 0.75

D. 0.9

Correct Answer: B

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Question 19

A plant has a genotype of Rr for a particular gene. If the plant is crossed with a plant having the genotype rr, what is the probability that the offspring will have the genotype RR?

Correct A. 0.25

B. 0.5

C. 0.75

D. 0.9

Correct Answer: A

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Question 20

A person has a blood type of AB and a Rh factor of positive. If the person's mother has a blood type of A and a Rh factor of negative, and the person's father has a blood type of B and a Rh factor of positive, what is the probability that the person's offspring will have a blood type of AB and a Rh factor of negative?

A. 0.25

B. 0.5

C. 0.75

Correct D. 0.9

Correct Answer: D

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Question 21

In a population of Drosophila melanogaster, the frequency of the recessive allele 'a' is 0.2. If the population is in Hardy-Weinberg equilibrium, what is the frequency of the homozygous dominant genotype 'AA'?

Correct A. 0.64

B. 0.36

C. 0.16

D. 0.04

Correct Answer: A

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Question 22

A cell is placed in a solution with a pH of 5.5. If the cell membrane has a permeability coefficient of 1.2 x 10^-6 cm/s, what is the concentration of hydrogen ions outside the cell?

Correct A. 1.2 x 10^-5 M

B. 1.2 x 10^-6 M

C. 1.2 x 10^-7 M

D. 1.2 x 10^-8 M

Correct Answer: A

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Question 23

A 5% solution of glu\cose is prepared by dissolving 5g of glu\cose in 95g of water. What is the concentration of the solution in g/100g?

Correct A. 5g/100g

B. 10g/100g

C. 15g/100g

D. 20g/100g

Correct Answer: A

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Question 24

A population of 1000 rabbits is introduced to an island. The population grows at a rate of 20% per year. What is the population after 5 years?

Correct A. 3241

B. 3248

C. 3256

D. 3264

Correct Answer: A

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Question 25

A 2.5g sample of a subs\tance is dissolved in 100g of water. What is the concentration of the solution in g/100g?

Correct A. 2.5g/100g

B. 5g/100g

C. 7.5g/100g

D. 10g/100g

Correct Answer: A

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