The exchange of segments of DNA between members of a pair of chromosomes during Meiosis... a) is called crossing
b) ensures that variations within a species never occur
c)acts as a source of variations within a species.
d)always produces genetic disorders

Environmental differences within ecosystems are generally caused by

Describe the relationship and movement between temperature and density in a convection cell. make sure you identify the direction of travel

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.