Which of the following compounds exhibits linkage isomerism?

$A$ block of mass $m$ is placed on a surface with a vertical cross-section given by $y = \frac{x^3}{6}$. If the coefficient of friction is $0.5$,the maximum height above the ground at which the block can be placed without slipping is

$A$ stick of length $L$ and mass $M$ lies on a frictionless horizontal surface on which it is free to move in any way. $A$ ball of mass $m$ moving with speed $v$ collides elastically with the stick at its end,as shown in the figure. If after the collision the ball comes to rest,then what should be the mass of the ball?

Match the common name given in column $I$ with their taxonomic category family given in column $II$ and choose the correct combination from the options given below.

Column-$I$ (Common Name)	Column-$II$ (Taxonomic category- Family)
$A$. Man	$I$. Poaceae
$B$. Datura	$II$. Anacardiaceae
$C$. Mango	$III$. Solanaceae
$D$. Wheat	$IV$. Hominidae

$A$ molecule $M$ associates in a given solvent according to the equation $nM \rightleftharpoons (M)_n$. For a certain concentration of $M$,the van't Hoff factor was found to be $0.9$ and the fraction of associated molecules was $0.2$. The value of $n$ is:

Which of the following is not a greenhouse gas?