Examples: hair color, skin color, height: probability rules, multiplication rule: independent events in sequence (and, example: a couple has 2 children. What is the probability they are both girls: addition rule: mutually exclusive events (or, example: a couple has 2 children. Understand when these laws apply and when not: monohybrid crosses uncovered the law of segregation and independent assortment. The pollen fertilized the ova, which developed into seeds. He then crossed 2 homozygous peas (homozygous round seed x homozygous wrinkled seed). If a cell contains 2 pairs of homologus chromosomes. in anaphase i of meiosis, each pair of homologus chromosomes separate independently. Unless they are located far enough apart that crossing over takes place in every meiotic division. Use a testcross to figure out the genotype of a trait. Phenotype is often obvious but genotype isn"t always due to dominant and recessive: a test cross is a way to figure out the genotype of a plant that is phenotypically dominant.