Relative method and carbon dating are the methods to know about evolution.

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

The two versions of a trait (character) which are brought in by the male and female gametes are situated on

$(a)$ "Each organism has its own identity". Explain.
$(b)$ What is speciation?

Give reasons for the following:
$(a)$ Traits acquired during the lifetime of an individual are not inherited.
$(b)$ All human beings belong to a single species.
$(c)$ Variations keep on accumulating during reproduction and do not disappear in the next generation.

Explain analogous organs and homologous organs. Identify the analogous and homologous organs amongst the following:
Wings of an insect,wings of a bat,forelimbs of frog,forelimbs of a human.