DNA synthesis occurs during
Interphase, a phase of the cell cycle, is the one in which a cell spends most of its life. During this phase, the cell copies its DNA in preparation for mitosis. The cell obtains nutrients, uses them to grow and conducts other "normal" cell functions. It was previously known as the resting phase although the cell is preparing for cell division at a later stage. It is divided into three phases:
1. G1 (first gap) - cell grows and functions normally. During G1, a large amount of protein synthesis occurs and the cell grows (to approximately double its original size) - a number of organelles are produced and the volume of the cytoplasm increases.
2. S (synthesis) - the cell duplicates its DNA or synthesizes DNA. For replication of DNA, histone proteins are required. Therefore, they are also synthesized during this phase.
3. G2 (second gap) - the cell resumes its growth in preparation for division.
The correct answer is option A.