Assertion: A middle aged woman is reported to have small breasts and undersized uterus.

Reason: Her genotypic analysis shows XO condition of allosomes.

• If both assertion and reason are true and reason is the correct explanation of assertion.

• If both assertion and reason are true but reason is not the correct explanation of assertion.

• If assertion is true but reason is false.

• If both assertion and reason are false

A tall true breeding garden pea plant is crossed with a dwarf true breeding garden pea plant. When the F₁ plants were selfed the resulting genotypes were in ratio of 

• 1:2:1 :: Tall heterozygous: Tall homozygous: Dwarf

• 3:1:: Tall: Dwarf

•  3:1:: Dwarf: Tall

•  3:1:: Dwarf: Tall

Pick out the correct statement.

I. Haemophilia is a sex-linked recessive disease
II. Down's syndrn=me is due to aneuploidy
III. Phenylketonuria is an autosomal recessive gene disorderIv. Sickle cell anaemia is an X-linked recessive gene disorder

• II and IV are correct

• I, III and IV are correct

• I, II and III are correct

• I, II and III are correct

In a test cross involving F_{1 di}hybrid flies, more parental-type offspring were produced that the recombinant type offspring. This indicates

• chromosomes failed to separate during meiosis

• the two genes are linked and present on the same chromosome

• both of the characters are controlled by more than one gene

• both of the characters are controlled by more than one gene

Match the terms in Column I with their description in Column II and choose the correct option. 

• A	B	C	D
  2	3	4	1

• A	B	C	D
  4	1	2	3

• A	B	C	D
  4	3	1	2

• A	B	C	D
  4	3	1	2

6.

Which of the following most appropriately describes haemophilia?

• X-linked recessive gene disorder

• Chromosomal disorder

• Dominant gene disorder

• Dominant gene disorder

Which of the following statements is not true for cancer cells in relation to mutations?

• Mutations destroy telomerase inhibitor

• Mutations inactivate the cell control

• Mutations inhibit production of telomerase

• Mutations inhibit production of telomerase

Which of the following statements is not true of two genes that show 50% recombination frequency?

• the genes may be on different chromosomes

• the genes are tightly linked

• the genes show independent assortment

• the genes show independent assortment

Variation in gene frequencies within populations can occur by chance rather than by natural selection. This is referred to as

• genetic flow

• genetic drift

• random mating

• random mating

If two persons with 'AB' blood group marry and have sufficiently a large number of children, these children could be classified as 'A' blood group in 1:2:1 ratio. The modern technique of protein electrophoresis reveals the presence of both 'A' and 'B' type proteins in 'AB' blood group individuals. This is an example of 

• codominance

• incomplete dominance

• partial dominance

• partial dominance