| A | B |
|---|
| sperm | male reproductive units |
| dominant | one allele will mask the expression of the other |
| testicles | the primary male organs of reproduction |
| ovum | eggs or gametes produced by the female in the ovary |
| gametes | sex cells produced for reproduction |
| heritability | the extent to which certain traits are controlled by the genetic material of an individual and transmitted to the offspring |
| embryo | a living being in the earliest stages of development |
| testosterone | a male hormone that governs secondary sex characteristics |
| fetus | an unborn or unhatched vertebrate in the later stages of development showing the main recognizable features of a mature animal |
| zygote | the cell produced by the union of gametes, fertilized eggs |
| cell | a unit of protoplasmic material with a nucleus and cell walls |
| estrogen | hormone that regulates the heat period |
| gestation | length of pregnany |
| heterozygous | pairs of genes that are different |
| hybrid | plant or animal offspring from crossing two different species or varieties |
| parturition | act of giving birth |
| progeny | offspring |
| mutation | change in genes |
| meiosis | cell division that results in the formulation of gametes |
| mitosis | simple cell division for growth |
