Guo Mao body photography 1034

A. In the process of individual development, the offspring of one or a kind of cells undergo different changes in morphology, structure and physiological functions, forming a variety of cells. This process is called cell differentiation. The result of cell differentiation is the formation of different tissues. A cell group composed of cells with similar morphology and the same structure and function is called a tissue. The cells of the same species have different sizes and shapes, but their basic structures are similar.

B, human cells have no cell walls, and red blood cells and platelets have no nuclei; B error;

C, is the result of cell division and growth, C error;

D, different structures complete different life activities, D is wrong.

So choose: a.