For a diatomic gas, which options is/are correct?

For an ideal diatomic gas:

For an ideal diatomic gas:

A diatomic gas will be obtained in

According to kinetic theory of gases, for a diatomic molecule, which is not correct

" Atomic number of diatomic gas which belong to third period is "

Assertion : The ratio C_(P)// C_(upsilon) for a diatomic gas is more than that for a monoatomic gas. Reason : The moleculess of a monoatomic gas have more degrees of freedom than those of a diatomic gas.

Assertion : The ratio C_(P)// C_(upsilon) for a diatomic gas is more than that for a monoatomic gas. Reason : The moleculess of a monoatomic gas have more degrees of freedom than those of a diatomic gas.

Assertion : The ratio C_(P)// C_(upsilon) for a diatomic gas is more than that for a monoatomic gas. Reason : The moleculess of a monoatomic gas have more degrees of freedom than those of a diatomic gas.

Oxygen is a diatomic gas. Why?