F.4 biology

Nucleus is not equal to nucleic acid.

Nucleus is a cellular comparment with a living cell (apart from mature RBC) which contains your genome (genetic material like DNA). It is a name like mitochondria that has no actual function on its own.

Nuclei acid is a chain of nucleotide (A, T, C and G). 2 complementary nucleic acids link to each other by hydrogen bonds and phosphodiester bonds to form a double helix structure.

So nucleic acid is the thing that carry your genetic information and nucleus is only the place where nucleic acid located in the cell.

nucleus is an organelle in a cell, it contain genes in it
but nucleic acid is an organic compound
it made up DNA and RNA
so they are entirely different in their size
their function and state

They are different of course.

Nucleus is a dense body made of proteins and nucleic acids and bound by the nuclear membrane. The functions of nucleus are used to control all life functions of the cell, control cell division and carry genetic material (in chromosomes) for heredity.