HEREDITY AND VARIATIONS - Jamb Biology Past Questions and Answers

Question 61:

• JAMB 2001

In man, the ability to roll the tongue is a variation classified as

A. Anatomical
B. Physiological
C. Structural
D. Morphological

Question 62:

• JAMB 2002

If X^N is the dominant allele for normal vision and Xⁿ the recessive allele for colour blindness, a boy with the genotype YXⁿ will be

A. Have normal vision
B. Be colour-blind
C. Be totally blind
D. Be a carrier of colour blindness

Question 63:

• JAMB 2002

The first four children of a couple were all girls. The probability that the fifth will also be a girl is

A. 1/5
B. 1/4
C. 1/3
D. 1/2

Question 64:

• JAMB 2002

Genetic counselling is important when a marriage is planned between a

A. Rh^- woman and Rh ^man+
B. Rh^- woman and Rh^- man
C. Rh⁺ woman and Rh⁺ man
D. Rh⁺ woman and Rh^- man

Question 65:

• JAMB 2002

What proportion of the offspring of a cross between two heterozygous parents will exhibit the recessive condition phenotypically

A. 1/4
B. 1/2
C. 3/4
D. 4/4