Which one of the following does not involve coagulation?

Let $f$ be a non-zero real-valued continuous function satisfying $f(x+y)=f(x) \cdot f(y)$ for all $x, y \in R$. If $f(2)=9$,then $f(6)$ is equal to

Two identical containers $A$ and $B$ with frictionless pistons contain an ideal gas at the same temperature and the same volume $V$. The mass of the gas in $A$ is $m_A$ and in $B$ is $m_B$. The gas in each cylinder is now allowed to expand isothermally to the same final volume $2V$. The changes in pressure in $A$ and $B$ are found to be $\Delta P$ and $1.5\Delta P$ respectively. Then:

$A$ particle falls from a height $h$ upon a fixed horizontal plane and rebounds. If $e$ is the coefficient of restitution,the total distance travelled before rebounding has stopped is

Select the incorrect statement from the following.

Match the following columns correctly:

Column-$I$	Column-$II$
$A$. Tapetum	$i$. Degenerates during development
$B$. Intine	$ii$. Resistant organic material
$C$. Vegetative cell	$iii$. Pollen tube
$D$. Sporopollenin	$iv$. Provides nourishment to pollen grains