JAMB Biology Past Questions & Answers - Page 194

966.

A health condition that is known to have resulted from gene mutation is

A.

typhoid

B.

rabies

C.

sickle-cell anaemia

D.

sleeping sickness

Correct answer is C

No explanation has been provided for this answer.

968.

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).

969.

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.

970.

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.