What is the initial stage of embryonic development known as?

The initial stage of embryonic development is known as the zygote. This stage occurs when a sperm cell successfully fertilizes an egg cell, resulting in a single diploid cell called a zygote. The zygote represents the very first step in the development of a new organism, containing a complete set of genetic material from both parents.

Following the zygote formation, it undergoes several rounds of cell division, leading to the morula stage, which is a solid ball of cells. Later, this develops into a blastocyst, which is a structure that will eventually implant in the uterine wall. The gastrula stage occurs even later, marking the beginning of tissue differentiation and organ formation. Thus, the zygote is correctly identified as the initial stage, laying the groundwork for further development.