Animals that give birth to young ones are known as:

Assertion $(S)$: Death is a meaningful event.
Reason $(R)$: Death keeps the number of organisms of each species limited.
$(A)$ Both $S$ and $R$ are true,$R$ is the correct explanation of $S$.
$(B)$ Both $S$ and $R$ are true,but $R$ is not the correct explanation of $S$.
$(C)$ $S$ is true and $R$ is false.
$(D)$ $S$ is false and $R$ is true.

After anther culture,some diploid plants are observed along with haploid plants. Which of the following parts induces the origin of the diploid plants?

Assertion : Pollen mother cells $(PMCs)$ are the first male gametophytic cells.
Reason : Each $PMC$ gives rise to two pollens.

Which of the following cells of the embryo sac degenerate after fertilisation in angiosperms?

The $Triticum$ $aestivum$ wheat is: