At what age do girls typically reach puberty (in $years$)?

Reproduction is essential for living organisms in order to

List any two modes of asexual reproduction in animals. Under which mode of reproduction is vegetative propagation placed and why? List two advantages of vegetative propagation.

What is the number of chromosomes in a human sperm cell?

State whether the following statement is true or false: $A$ thick and spongy lining of the uterus is required for nourishing the embryo if fertilization has taken place.

In the process of grafting,what is the term for the rooted plant part that is fixed in the soil?