2020 - JAMB Biology Past Questions and Answers - page 3

21

The ability of the eyes to focus on both near and distance objects is termed

A

image formation

B

refraction

C

hypermetropia

D

accommodation

correct option: d

Accommodation is the process by which the vertebrate eye changes optical power to maintain a clear image or focus on an object as its distance varies. Wikipedia

When our eyes see distant objects then the ciliary muscles relax and the focal length is maximum in this position.

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22

A group pf organism of different species living in a particular area is described as a

A

colony

B

community

C

population

D

niche

correct option: b

Community, also called biological community, in biology, an interacting group of various species in a common location

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23

The biological association that contributes directly to succession in a community is

A

competition

B

predation

C

parasitism

D

commensalism

correct option: a

 

Competition is an interaction between organisms or species in which both the organisms or species are harmed. 

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24

Floating microscopic heterotrophs are mostly grouped as

A

phytoplankton

B

zooplankton

C

microbes

D

nekton

correct option: a

Phytoplanktons are microscopic marine organisms at the bottom of the food chain. Most phytoplanktons are buoyant and float in the upper part of the ocean.

Phytoplanktons are the autotrophic components of the plankton community and a key part of ocean and freshwater ecosystems.

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25

Vaccination is carried out in order to

A

check the production of poison

B

increase the activities of white blood cells

C

increase the number of red blood cells

D

stimulate the production of anti-bodies

correct option: d
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26

For growth to occur in organisms, the rate of

A

anabolism must exceed that of catabolism

B

catabolism must exceed that of anabolism

C

food storage must be low

D

food storage must be high

correct option: a

Anabolism is the set of metabolic pathways that construct molecules from smaller units. These reactions require energy, known also as an endergonic process. Anabolism is the building-up aspect of metabolism, whereas catabolism is the breaking-down aspect.

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27

The probability of a baby being a boy or a girl depends on the contribution of the

A

father's sex cells

B

father's stomatic chromosome

C

mother's sex cell

D

mother's X-chromosome

correct option: a

A man with many brothers is more likely to have sons, while a man with many sisters is more likely to have daughters.

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28

Both recesssive and dominant characters are found

A

on different chromosome in the cell

B

at the same logus of a homologous chromosome

C

at a different loci of a homologous chromosome

D

on the same chromatid in a chromosome

correct option: b
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29

In a popu;ation of living things, the parameters of size, height, weight and colours are examoles of

A

continuous variation

B

non-heritable variation

C

discontinuous variation

D

physiological variation

correct option: a

Continuous variation is the combined effect of many genes (known as polygenic inheritance) and is often significantly affected by environmental influences.

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30

Use the diagram to answer the question.

The process of water loss and intake indicated by the arrows labelled i and ii are respectively

A

evaporation and osmosis

B

exhalation and osmosis

C

osmosis and diffusion

D

urination and diffusion

correct option: b
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