| A | B |
|---|
| heredity | the passing of physical characteristics from parents to offspring |
| trait | each different form of a characteristic, such as stem height or seed color |
| genetics | the scientific study of heredity |
| fertilization | a process during which a new organisms begins to form when an egg and sperm join |
| purebred | an organism that is the offspring of many generations that have the same trait |
| gene | the factor that controls a trait |
| alleles | the different forms of a gene |
| dominant allele | an allele whose trait always shows up in the organism when the allele is present |
| recesive allele | an allele that is hidden whenever the dominant allele is present |
| hybrid | an organism that has two different alleles for a trait |
| probability | a number that describes how likely it is that an event will occur |
| Punnett square | a chart that shows all the possible combinations of alleles that can result from a genetic cross |
| phenotype | an organism's physical appearance, or visible traits |
| genotype | an organism's genetic makeup, or allele combinations |
| homozygous | an organism that has two identical alleles for a trait |
| heterozygous | an organism that has two different alleles for a trait |
| codominance | when the alleles are neither dominant nor recessive |
