During his observation of spermatogenesis in a few insects, Henking found that a nuclear structure was received by 50 % of the sperms. He called this structure as:

1.	X – body	2.	Y–body
3.	X – chromosome	4.	Y – chromosome

The expression of only one of the parental characters in a monohybrid cross in the F₁, the expression of both in the F₂ and the proportion of 3:1 obtained at the F₂ can be explained by:
1. Law of Dominance
2. Law of segregation
3. Law of Independent Assortment
4. Two-factor interaction

Which of the following is not an X – linked recessive disorder in humans?

When there is a change in the chromosome number such that the changes number is not an exact multiple of base number [haploid number], the condition is called as:

On self-pollinated a tall F₂ plant, the progeny can be:

Mutations that arise due to changes in a single base pair of DNA are called as:

The inheritance of I^A and I^B allele exhibit:

In humans, the mechanism of sex determination is:

When Morgan hybridised yellow-bodied, white-eyed females to brown-bodied, red-eyed males and intercrossed their F₁ progeny, the F₂ ratio deviated very significantly from the 9:3:3:1 ratio. This can be attributed to the fact that:

In a dissimilar situation, the unit factor that expresses itself is called as: