I think the correct answer from the choices listed above is option C. The substitution, addition, or removal of a single nucleotide in DNA is called a point mutation. It is a type of mutation that affects only one or very few nucleotides in a gene sequence.
Nuclear Membrane separates the contents of nucleus from the cytoplasm.
Explanation:
Two nuclear membranes form a nuclear envelope that separates the nuclear contents from the cytoplasmic content of the cell.These run continuous with the endoplasmic reticulum enclose a perinuclear space in between them.The nuclear membrane contain nuclear pore that control exit and entrance of molecules coming in and leaving the nucleus.
I think its A but it has been a while since i did this.