JAMB Biology Past Questions & Answers - Page 193

961.

The nephridia in the earthworm form part of the

A.

reproductive system

B.

respiratory system

C.

circulatory system

D.

excretory system

Correct answer is D

In earthworms, members of the phylum Annelida, the excretory system consists of structural units called nephridia (the singular is nephridium).

962.

A farmer's assumption that the seed from a good harvest will produce a good yield is explained by the theory of

A.

evolution

B.

adaptation

C.

variation

D.

heredity

Correct answer is D

No explanation has been provided for this answer.

963.

A phenotypic character with intermediate forms that can be graded from one extreme to the other is referred to as?

A.

discontinuous variation

B.

continuous variation

C.

a mutant

D.

a genome

Correct answer is B

Variations can be:

  • Discontinuous or discrete and is often caused by the presence or absence of a small number of genes.

We can all either roll our tongue or not; there's nothing in between.

Others are Eye colour, handedness, & lobed/lobeless ears.

  • Continuous or quantitative, smoothly grading between two extremes: Hand span, arm length, & height. 

964.

The uniqueness of an individual organism in a population is accounted for by

A.

evolution

B.

variation

C.

adaptation

D.

mutation

Correct answer is B

Variation is the difference between individuals within a species.

Variations could occur by inherited or acquired characteristics.

965.

The major cause of global warming is

A.

burning fossil fuel

B.

constructing dams

C.

electricity utilization

D.

space exploration

Correct answer is A

As greenhouse gas emissions blanket the Earth, they trap the sun’s heat. This leads to global warming and climate change.

This global warming is caused by increased concentrations of greenhouse gases in the atmosphere, mainly from human activities such as burning fossil fuels, and farming.

  • Burning fossil fuels. 
  • Deforestation & Tree-Clearing.