Why is reproduction essential for organisms?

Is the number of eggs laid by oviparous animals equal to the number of offspring produced by viviparous animals? Why?

In $P$ type of plants,vegetative,reproductive,and senescent phases are clearly visible,whereas in $Q$ type of plants,it is difficult to clearly define these phases.
$\quad\quad\quad\quad P \quad\quad\quad\quad Q$
$(A)$ Annual $\quad$ Biennial,Perennial
$(B)$ Annual,Biennial $\quad$ Perennial
$(C)$ Perennial $\quad$ Annual,Biennial
$(D)$ Biennial,Perennial $\quad$ Annual

Differentiate between asexual reproduction and sexual reproduction.

Which organism does not have heterogametes?

Select the correct statement.