Which of the following is a source of thermal energy that is absorbed by Earth's atmosphere?

100% of the energy entering earth's atmosphere comes from the sun. ~50% of the incoming energy is absorbed by the earth's surface i.e. the land and oceans.

a lot of it means it can be "burned" for energy and sold at one price. if it is scarce, the price will go up

when two balls of the different masses are dropped from equal height, they reach the ground at the same time .this is because they experience the same acceleration.

the acceleration is independent of mass.

thus when they are dropped they will always maintain the same velocity and travel the same distance (neglect air resistance of course) at the same time.