The correct answer is (a) (i) and (ii).
Explanation:
For a new species to form, significant changes in the genetic material are necessary. This can occur through alterations in DNA within germ cells (the cells that produce gametes) or changes in the chromosome number within the gametes themselves. If there is no change in the genetic material (option iii), then no new species will form as the offspring will be genetically identical to their parents. Mating does not directly lead to the formation of new species; it is the process of fertilization and the subsequent inheritance of altered genetic material that can contribute to speciation.
Why other options are incorrect:
(b) (i) and (iii):
While DNA changes in germ cells are crucial for speciation, no change in the genetic material contradicts the concept of evolution and the formation of new species.
(c) (ii), (iii), and (iv):
A change in chromosome number can contribute to speciation, but the absence of genetic change and the lack of mating would prevent the formation of a new species.
(d) (i), (ii), and (iii):
Option (iii) contradicts the necessary condition for speciation, which is a change in the genetic material.