Question 536:

• JAMB 1987

The ratio of carriers to sicklers in the F₁ generation derived from a parental cross of two carriers of haemoglobin S gene is

A. 3 : 1
B. 1 : 3
C. 2 : 1
D. 1 : 2

Question 537:

• JAMB 1987

In which of the following crosses will all the female offspring be colour blind?

A. Colour blind mother x colour blind father
B. Colour blind mother x normal father
C. Carrier mother x colour blind father
D. Carrier mother x normal father

Question 538:

• JAMB 1987

Which of the following relates to edaphic factors?

A. The structure of the earth's surface
B. The influence of living organisms on each other
C. Temperature, rainfall and humidity
D. The influence of soils on plant and animals

Question 539:

• JAMB 1987

Epiphytes growing on the branches of trees provide an example of the relationship known as

A. Parasitism
B. Commensalism
C. Saprophytism
D. Holophytism

Question 540:

• JAMB 1987

Poliomyelitis is an infectious diseases caused by

A. Virus
B. Protozoan
C. Bacterium
D. Fungus