In the given figure,what is the bond angle represented by '$a$' (in $^\circ$)?

Vitamin $C$ is

Which of the following is a correct sequence for the appearance of compounds in a cell?

Pellagra is caused by the deficiency of

The given diagrammatic representation shows one of the categories of small molecular weight organic compounds in living tissues. Identify the category shown and the one blank component "$X$" in it.

Which of the following are included in organic components?