A zygote which has an X-chromosome inherited from the father will develop into a

In human males all the chromosomes are paired perfectly except one. This/these unpaired chromosome is/are

I. large chromosome

II. small chromosome

III. Y-chromosome

IV. X-chromosome

The maleness of a child is determined by

Select the incorrect statement

New species may be formed if

i. DNA undergoes significant changes in germ cells

ii. chromosome number changes in the gamete

iii. there is no change in the genetic material

iv. mating does not take place