WEBVTT 00:00.000 --> 00:02.367 During the first 8 weeks following fertilization, 00:02.400 --> 00:05.167 the developing human is called an embryo, 00:05.200 --> 00:09.667 which means "growing within." 00:09.700 --> 00:12.700 This time, called the embryonic period, 00:12.733 --> 00:14.700 is characterized by the formation 00:14.733 --> 00:17.333 of most major body systems.