What does a virus contain?

The correct order of $C-O$ bond length in $CO$,$CO_3^{2-}$,and $CO_2$ is:

The plates of a parallel plate capacitor are charged up to $100\;V$. $A$ $2\;mm$ thick plate is inserted between the plates. Then,to maintain the same potential difference,the distance between the plates is increased by $1.6\;mm$. The dielectric constant of the plate is:

The greatest threat to genetic diversity in agricultural crops is

Curie temperature is the temperature above which

If $R$ is the radius of the Earth and $g$ is the acceleration due to gravity on the Earth's surface,then the mean density of the Earth is ..........