Which animal possesses neurons but lacks a brain?

Consider the following reaction: $C_6H_5NO_2$ $\xrightarrow{Sn/HCl} X$ $\xrightarrow{C_6H_5COCl} Y + HCl$. What is $Y$?

Cataract and skin cancer are caused by

The $Ca^{2+}$ and $F^{-}$ ions are located in a $CaF_{2}$ crystal,respectively,at face-centered cubic lattice points and in:

The ionization energy of $He^+$ is $19.6 \times 10^{-18} \ J \ atom^{-1}$. What is the energy of the first stationary state $(n = 1)$ of $Li^{2+}$?

If the mean and variance of a binomial variate $X$ are $8$ and $4$ respectively, then $P(X < 3)$ equals to