1. the inheritance of biological characteristics is determined by individual units known as genes. Genes are passed from parents to their offspring
2. In cases in which two or more forms of the gene for a single trait exist, some forms of the gene may be dominant and others may be recessive.
3.sexually reproducing animals have two two copies of each gene - one from each parent. They segregate from each other when gametes are formed.
4. Alleles from different genes usually segregate from each other.