Heredity And Variations - Biology Jamb Past Questions and Answers

Question 26 :

• JAMB 1989

Which of the following is a sex-linked character?

A. Sickle-cell anaemia
B. Tongue rollling
C. Skin colour
D. Colour blindness

Question 27 :

• JAMB 1990

In organism where the 2nd number of chromosomes is 16, the number of chromosomes in each gamete will be

A. 32
B. 16
C. 8
D. 4

Question 28 :

• JAMB 1990

What will be the result of the first filial generation (F₁) and the second filial generation (F₂) of a mono-hybrid cross between pure line normal-winged Drosophilia flies and pure line short-winged flies, if the gene for the normal wing is dominant?

A. F₁ flies all short-winged and F₂ flies all normal-winged
B. F₁ flies all normal and F₂ flies all short-winged
C. F₁ flies all short-winged and three-quarters of F₂ flies are short-winged
D. F₁ flies all normal-winged and three-quarters of F₂ flies are normal-winged

Question 29 :

• JAMB 1991

The exchange of genes between homologous chromosomes is called

A. Test cross
B. Back cross
C. Crossing-over
D. Mutation

Question 30 :

• JAMB 1991

When two heterozygotes mate, the dominant trait will appear in

A. The F₁ generation only
B. The F₂ generation only
C. Both the F₁ and F₂ generations
D. Neither the F₁ nor F₂ generation