Plain - flat or Rolling Land with few changes in elevation
The answer to the question is the total surface area increases and chemical composition changes. Consider the breakdown of rock into smaller pieces, these fragments vary from huge rocks to smaller sizes. As they are so crushed and broken they tend to occupy much of the surface area than when its just a huge rock.
Answer:
All of the energy from the Sun that reaches the Earth arrives as solar radiation, part of a large collection of energy called the electromagnetic radiation spectrum. Solar radiation includes visible light, ultraviolet light, infrared, radio waves, X-rays, and gamma rays. Radiation is one way to transfer heat.