In which component is a heterocyclic ring found?

Which of the following statements are correct?
$(a)$ Proteins are heteropolymers of amino acids.
$(b)$ The sugar found in nucleic acids is of the $\beta$-type.
$(c)$ Nucleic acids exhibit acidic properties.
$(d)$ $5$-methyl uracil is attached to the first carbon atom of the ribose sugar.
$(e)$ Collagen is the most abundant protein found in the plant kingdom.

Which bond is degraded by hydrolysis?

Porphyrin is found in which of the following?

Which of the following vitamins is present in cod-liver oil?

The primary precursor for the production of cholesterol in our body is