| A | B |
|---|
| fertilization | the combining of an egg and sperm cell |
| heredity | when traits are passed from parents to children |
| chromosome | tiny parts of a cell which carry hereditary traits |
| umbilical cord | carries oxygen and nutrients from the mother to the fetus |
| fetus | a developing unborn baby |
| puberty | a time when a human physically matures into an adult |
| pituitary gland | produces human growth hormone |
| testes | makes sperms and male sex hormone |
| ovaries | makes egg cells and female hormones |
| hormones | substances produced by glands and control body functions |
| fraternal twins | begin as 2 fertilized cells and look different |
| identical twins | begin from 1 cell //have the same appearance and sex |
