21.

What happens when :
Bryophyllum leaf falls on the wet soil?

What happens when :
On maturation sporangia of Rhizopus bursts?

State the basic requirement for sexual reproduction? Write the importance of such reproductions in nature.

State the changes that take place in the uterus when :
Implantation of the embryo has occurred.

State the changes that take place in the uterus when :
Female gamete/egg is not fertilised

Explain with the help of an example each, how the following provides evidence in favour of evolution:
Homologous organs

Explain with the help of an example each, how the following provides evidence in favour of evolution:
Analogous organs

Explain with the help of an example each, how the following provides evidence in favour of evolution:
Fossils