Which of these choices is the definition of allele? :) A: the form of a gene that is expressed
B: one of the alternative forms of a gene
C: the combination of genes for a specific trait
D: the complete genetic makeup of a living thing

During the winter, this species of fox has white fur, but in the summer, it has brown fur. what environmental change may have lead to this fox's fur color? snow cover increase in sun's brightness volcanic eruption global warming

Which locations on the map are low-pressure areas? a b c d e

Drag each tile to the correct box. the body monitors the levels of oxygen in the blood to regulate breathing. isabel is running in a marathon and is near the finish line. she feels out of breath. how will her nervous system work to generate a reaction? arrange the tiles in chronological order. isabel's breathing rate increases. sensory receptors in the arteries detect low oxygen levels. the brain sends signals through motor neurons. sensory neurons generate an impulse. the central nervous system relays an impulse to certain brain regions.