How does the circulatory system work at the organ level? The heart pumps the blood.

Cardiac muscle contracts.

Blood cells carry nutrients.

Nutrients are delivered throughout the body.

Advances in technology have enabled scientists and researchers to better study the evolutionary relationships between species

Two critical interventions to turn around the opioid crises are:

Amale bird-of-paradise uses a dance to attract mates in which it flaps its tail feathers on the ground and jumps around a potential female mate. a different male bird-of-paradise does a similar dance but it jumps around the female in the opposite direction. the female bird is only attracted to one style of dance, in one direction.