| A | B |
|---|
| dominant | One of a pair of alternative alleles that masks the effect of the other when both are present in the same cell or organism. |
| recessive | One of a pair of alternative alleles whose effect is masked by the activity of the second when both are present in the same cell or organism. |
| Punnett Square | A grid that can indicate all the possible outcomes of a genetic cross. |
| purebred | An organism that always produces offspring with the same form of a trait as a parent. |
| hybrid | An organism that has two different alleles for a trait. |
| heterozygous | Having two different alleles for a trait. |
| homozygous | Having two identical alleles for a trait. |
| genotype | An organism's genetic makeup, or allele combination. |
| phenotype | An organism's physical appearance, or visible traits. |
| codominance | A condition in which neither of the two alleles of a gene is dominant or recessive. |
| fulcrum | The point about which a lever pivots. |
| lever | Any rigid rod or plank that pivots, or rotates about a point. |
| inclined plane | A flat, sloped surface. |
| wedge | An inclined plane that moves. |
| screw | An inclined plane wrapped around a cylinder or post. |
| wheel & axle | A simple machine that consists of two circular objects of different sizes that are attached in such a way that they rotate together. |
| force | An influence on the shape, motion, or other characteristics of a body or system. |
| pulley | A wheel or set of wheels with grooved edges over which a rope or chain can be drawn in order to change the direction of a pulling force and increase the capacity for lifting weight. |
| friction | The resistance of a surface to relative motion, as of an object sliding or rolling over it. |
| wheel | Any instrument, device, or apparatus resembling such a disk or frame in shape, motion, or function. |
