5 Easy Facts About plastic surgery Described
During embryonic growth the cells of the internal cell mass continuously divide and develop into more specialized. As an example, a portion of the ectoderm from the dorsal part of the embryo specializes as 'neurectoderm', that may develop into the future central anxious system (CNS).아래에 가라 앉은 액체층과 맨 위 기름층은 처음