Fill in the blanks and select the correct option:
(i) _____A_____ could trace a specific nuclear structure, all through spermatogenesis in a few insects.
(ii) Grasshopper is an example of ____B_____ type of sex determination.
(iii) Male bird is _____C____
(iv) Rest of the chromosomes, except sex chromosomes, are known as ____D____ .

Options

A. (A - Henking), (B – XO), (C - Heterogametic), (D - Autosomes)
B. (A - Morgan), (B – XY), (C – Homogametic), (D - Autosomes)
C. (A - Hugo de Vries), (B - XO), (C - Heterogametic), (D - Autosomes)
D. (A - Henking), (B – Xo), (C – Homogametic), (D – Autosomes)

Answer

D

Explanation

Henking is the one who first observed X-body during spermatogenesis of male bug and described about X-body.
XO-system is used in sex determination of grasshopper. There is only one sex chromosome referred to as X.
Male grasshopper is heterogametic XO and female grasshopper is homogametic XX.
Therefore, the sex of animals. offspring will depend on whether a sex chromosome is present in the male gamete or not.
Sex chromosome of birds is designated as Z and W. Male bird is homogametic ZZ and female bird is ZW heterogametic.
There are 23 pairs of chromosome in which 22 pairs are called autosomes and 23rd chromosome is called sex chromosome or allosomes. The sex chromosomes in humans are XX in females and XY in males.
Thus, males are responsible for the sex of the offspring.