What are substances that cannot be broken down into simpler substances?

molecules

elements

compounds

protons

Which of the following characteristics of earth's relationship to the sun explains the existence of earth's seasons? choose all that apply. earth has a satellite called the moon, which rotates around earth. earth spins on its axis, completing one rotation each day. earth's axis always points in the same direction relative to the stars. earth's axis is tilted relative to its orbital plane. earth orbits around the sun, completing one orbit each year.