Which of the following is a non-living level of biological organization?

In a compound,$C$,$H$,and $N$ atoms are present in the ratio $9 : 1 : 3.5$ by weight. The molecular weight of the compound is $108$. Its molecular formula is:

$A$ light and a heavy body have equal kinetic energy. Which one has a greater momentum?

Two circular coils $A$ and $B$ are facing each other as shown in the figure. The current $i$ through coil $A$ can be altered.

In a compound microscope,the focal lengths of two lenses are $1.5 \ cm$ and $6.25 \ cm$. An object is placed at $2 \ cm$ from the objective lens and the final image is formed at $25 \ cm$ from the eye lens. The distance between the two lenses is $.... \ cm$.

In $P-N$ junction,the barrier potential offers resistance to