The classical astronomers concluded that heavens were made up of a sphere, because heavens were thought to be perfect and spheres (circles) are a perfect shape. It was Plato who argued that geometrical figures were spheres and everyone agreed to him. It was also believed that the perfect motion of spheres was a uniform circular rotation.
Answer: Hetrotypes are organisms (anything that lives) that can make it's own energy without absorbing it from other organisms. Example: Flowers, they get there energy from the sun, not from eating and absorbing other organisms.
