Which of the following structures contains its own $DNA$?

$A$ vertical spring with force constant $k$ is fixed on a table. $A$ ball of mass $m$ at a height $h$ above the free upper end of the spring falls vertically on the spring so that the spring is compressed by a distance $d$. The net work done in the process is

What is the maximum number of rectangular components into which a vector can be split in space?

If $f(x) = \frac{x}{1+x}$ and $g(x) = f(f(x))$, then $g^{\prime}(x)$ is equal to

Which of the following is a polyamide?

$\int_{-2}^2 |[x]| \, dx$ is equal to