True nucleus is absent in

Which is the correct option for sulphur-containing amino acids?

The points with position vectors $60i + 3j$,$40i - 8j$,and $ai - 52j$ are collinear if $a = \dots$

In the random experiment of tossing two unbiased dice,let $E$ be the event of getting the sum $8$ and $F$ be the event of getting even numbers on both the dice. Then:
$I. P(E) = \frac{7}{36}$
$II. P(F) = \frac{1}{3}$
Which of the following is a correct statement?

If the line $2x + 5y = 12$ intersects the ellipse $4x^2 + 5y^2 = 20$ in two distinct points $A$ and $B$,then the mid-point of $AB$ is