Fig. 23-17. A human fetus undergoes considerable change in body proportions during 

 gestation. These five are compared as to relative size and body shape. Their approxi- 

 mate ages are 8 weeks, 12 weeks, 16 weeks, 6 months, and full term. 



prenatal 



birth 



adult 



Fig. 23-18. Various parts of the body grow at different rotes during the life of an animal. Here in the human being 

 many changes occur from prenatal life at the left to the adult at the right. Note particularly the proportionate 

 difference in the head and body size. 



