Antihistamines and steroids are administered for which of the following?

The centre of mass of a body

The variance of $20$ observations is $5$. If each observation is multiplied by $2$,then the variance of the resulting observations is:

How many types of sporophylls are found in Pteridophytes?

If $f:[2,3] \rightarrow R$ is defined by $f(x)=x^3+3x-2$, then the range of $f(x)$ is contained in the interval

See the diagram. The area of each plate is $2.0\ m^2$ and $d = 2 \times 10^{-3}\ m$. $A$ charge of $8.85 \times 10^{-8}\ C$ is given to plate $Q$. Then the potential of $Q$ becomes......$V$.