Question

what is the length of gestation for a baby and how is the age determined?

Explanation:

The average length of human gestation is about 40 weeks from the first - day of the last menstrual period. Gestational age can be determined by several methods. First, by calculating from the last menstrual period. Second, through ultrasound in early pregnancy which measures the size of the embryo or fetus to estimate age. Third, physical examination of the fetus later in pregnancy can also give an estimate based on fetal size, position and other factors.

Answer:

The average length of gestation is about 40 weeks. Age can be determined by last - menstrual - period calculation, ultrasound, and physical examination of the fetus.