Which of the following is an example of Disciflorae?

In the expansion of $(1+x)^n$,the coefficients of the $p^{th}$ and $(p+1)^{th}$ terms are respectively $p$ and $q$. Then $p+q$ is equal to:

Which of the following molecules has the highest dipole moment?

........ of a reaction cannot be determined experimentally.

Which one of the following characters is not typical of the class Mammalia?

The point of intersection of the diagonals of a square is at the origin,and the coordinate axes are drawn along the diagonals. If the side length of the square is $a$,which of the following is $NOT$ a vertex of the square?