Which of the following is a characteristic feature of living organisms?

$X$ - No non-living objects exhibit metabolism.
$Y$ - Metabolic reactions can be demonstrated outside the body in a cell-free system.

Assertion: Living organisms are regarded as closed systems.
Reason: Energy of living organisms cannot be lost or gained from the external environment.

Which of the following $statement(s)$ is/are correct?

Two plants are said to belong to the same species if they...

$S$ Statement: Reproduction leads to an increase in the number of organisms.
$R$ Reason: In reproduction,organisms produce new individuals similar to themselves upon reaching maturity.
$(a)$ Both $S$ and $R$ are true,and $R$ 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.