The chances of hereditary and evolutionary changes are higher in species that reproduce through:

What is gamete transfer? State its necessity.

What is the viability period of pollen grains in members of the families $Rosaceae$,$Leguminosae$,and $Solanaceae$?

Match the following columns:

List-$I$	List-$II$
$(a)$ Stamen	$(i)$ Microsporangium
$(b)$ Pistil	$(ii)$ Microsporophyll
$(c)$ Anther	$(iii)$ Megasporangium
$(d)$ Ovule	$(iv)$ Megasporophyll

Given below are two statements: One is labelled as Assertion $(A)$ and the other is labelled as Reason $(R)$.
Assertion $(A)$: Both wind and water pollinated flowers are not very colourful and do not produce nectar.
Reason $(R)$: The flowers produce an enormous amount of pollen grains in wind and water pollinated flowers.
In the light of the above statements, choose the correct answer from the options given below:

Bisexual flowers which never open are known as: