What does the following figure represent?

$A$ thin circular ring of mass $M$ and radius $R$ is rotating about its axis with a constant angular velocity $\omega$. Two objects,each of mass $m$,are attached gently to the opposite ends of a diameter of the ring. The ring now rotates with an angular velocity:

Which of the following is the most stable?

When an ideal diatomic gas is heated at constant pressure,the fraction of the heat energy supplied which increases the internal energy of the gas is:

The presence of a nitro group in a benzene ring.....

Foetal ejection reflex in human female is induced by