The preserved traces of all living organisms are called fossils.

$(a)$ State any two factors that could lead to the rise of a new species.
$(b)$ How do analogous organs provide evidence in favour of evolution?

Differentiate between inherited and acquired characters. Give one example for each type.

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

What evidences can suggest that, "Modern human beings have originated in Africa"?

In human beings,the statistical probability of getting either a male or female child is $50 : 50$. Give a suitable explanation.