In which of the following organisms does growth occur throughout their lifespan?

Length of the stem at time $0$ is $20 \ cm$. The arithmetic growth rate is $30 \ cm$ per day. What is the length of the stem at the end of the $7^{th}$ day (in $cm$)?

In the sigmoid growth curve,the alphabets indicate the sequence of events. Choose the correct option where the alphabet specifies the event.

Growth is measured by a variety of parameters,some of which are an increase in:
$a.$ Dry weight
$b.$ Fresh weight
$c.$ Volume
$d.$ Cell number

Living organisms increase in body size after their birth. This phenomenon is associated with which of the following?

Assertion $(S)$: Growth occurs when anabolic processes exceed catabolic processes.
Reason $(R)$: Growth is the result of metabolism.
$(A)$ 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.