If a female having gene for haemophilia and colour-blindness on one X-chromosome marries a normal male, then what are the chances in their offspring?
1. 50% sons diseased and 50% normal
2. All normal offspring
3. 100% daughters are carrier
4. 100% sons diseased

Reason for trisomy in Down's syndrome is:
1.  Non-disjunction during sperm formation
2.  Non-disjunction during egg formation
3.  Non-disjunction at the time of egg or sperm formation
4.  Addition of one extra chromosome during mitosis

Mental retardation in man occurs due to:
1. Loss of one X chromosome
2. Addition of one X chromosome
3. Slight growth in Y
4. Overgrowth in Y

ABO blood group has:
1.  Two codominant and one recessive allele
2.  Two codominant and two recessive allele
3.  Two incompletely dominant genes
4.  Two pseudo alleles

A normal woman, whose father was colour-blind is married to a normal man. The sons would be:
1. 50% colour-blind
2. All normal
3. All colour-blind
4. 75 % colour-blind 

Lack of independent assortment of two genes A and B in the fruit fly Drosophila is due to:

1. Recombination

2. Linkage

3. Crossing over

4. Repulsion 

In a plant red fruit (R) is dominant over yellow fruit (r) and tallness (T) is dominant over shortness (t). If a plant with RRTt genotype is crossed with a plant that is rrtt:

1. 50% will be tall with red fruit

2. 75% will be tall with red fruit

3. All the offspring will be tall with red fruit

4. 25% will be tall with red fruit

What change occurs by changing one base in DNA:
1.  Always a change of one amino acid in protein
2.  Change in complex sequence of amino acid
3.  Always a change in property of protein
4.  Does not necessarily change the phenotype

The allele for tallness is dominant over that of dwarfness. This is called:
1.  Law of independent assortment
2.  Law of segregation
3.  Law of unit character
4.  Law of dominance

What ratio is expected in offsprings if father is colour blind and mother's father was colour blind:
1.  50% daughter – colour blind
2.  All the sons are colour blind
3.  All the daughters colour blind
4.  All the sons are normal