Answer:
From fertilization and to the end of the second week.
Explanation:
The development of the fetus is divided into three periods, established by most embryologists: pre-embyonic period, which goes from fertilization to the second week of development, embryonic period, which goes from the third week to the eighth week, and the fetal period, which goes from from the third month until the end of pregnancy.
The pre-embyonic stage begins at fertilization and remains until gastrulation. By the end of the second week the embryo already has the neural tube formed, although it is still open at both ends.
A. Protein powers the body.
Place it on the side of your windpipe, and wen u count ,.. count the number of beats in 15 seconds..like feel the bone of ur jaw line.. and push in. the when u feel a beat there u go.. sometimes u may have to hold your breath to focus on the beat
