Which of the following is a secondary pollutant?

If $(1, a)$ and $(b, 2)$ are conjugate points with respect to the circle $x^2+y^2=25$,then $4a+2b$ is equal to

$F_{pp}$,$F_{nn}$,and $F_{np}$ are the nuclear forces between proton-proton,neutron-neutron,and neutron-proton respectively. Then the relation between them is:

Which of the following is the most stable?

Which of the following is the richest source of protein?

The number of divisors of $n = 38808$ (excluding $1$ and $n$) is