Nan is pregnant with her first child. she just found out that the baby has grown 1 pound since her last doctor's appointment. she is in the period of prenatal development.

The duration of pregnancy, on average it ranges from 266 days or 38 weeks. There are two periods in the pregnancy that are: Embryonic period and the fetal period.

First eight weeks are in the embryonic period and from 9th week to birth is in the fetal period.

cell regulation is conducted by special proteins.

and after water is usually warmed by the sun the water temperature raises and then evaporates .