The correct answer is circular. Copernicus and other astronomers before him thought that celestial bodies followed a circular orbital path. Copernicus was a Polish astronomer that concluded that the sun is at rest near the center of the universe and the earth is revolving around it annually. This theory is called heliocentric.
The answer is C because water moves from an are to low solute concentration to an area of high solute concentration.
D. population and nutrients
The basic unit of structure and function is cells
To prevent blood flowing back after each heartbeat. They ensure that the blood flows only in one direction (back to the heart).
