In the structure of nucleic acids,in which of the following forms is phosphoric acid incorporated?

In a water molecule,at what angle are the $H - O - H$ bonds connected (in $^\circ$)?

Vitamins are:

Which of the following is the structure of thymine?

Which of the following protects from scurvy?

Assertion $(S)$: The measure of disorder in a biological system is called free energy.
Reason $(R)$: The energy available in a biological system to perform work is called entropy.
$(A)$ Both $S$ and $R$ are true,and $R$ is the correct explanation of $S$.
$(B)$ Both $S$ and $R$ are true,but $R$ is not the correct explanation of $S$.
$(C)$ $S$ is true and $R$ is false.
$(D)$ $S$ is false and $R$ is true.
$(E)$ Both $S$ and $R$ are false.