On a velocity - time graph, if the line crosses the x - axis it depicts that the object has started moving in the opposite direction.
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.
<span>Antimony I am pretty sure is one. </span>