Question

What is the main source of energy for Earth?
A) Moon
B) Plants
C) Humans
D) Sun

Answer 1

We need to understand the mechanisms in which the living things on the planet earth and other elements gain the required energy for survival. The reason for earth being the only planet that supports life can also be the answer to this.

Complete answer:
Earth is the only planet so far which can support life for the carbon-based living organisms. It is entitled with the luxury of ample amounts of heat, light and air which will help the living things such as plants and animals to live, grow and multiply on this planet. We can understand that all the plants, animals and human beings require the heat and light from the sun for living.

The plants which are the primary producers in the food cycle use the sunlight for the production of edible products by the process of photosynthesis. It also is the ultimate source for the oxygen which supports aerobic respiration in higher animals.
The energy from the sun is the reason for most of the energy forms on the planet. The optimum temperature which is maintained by the suitable distance from the sun keeps water as liquid for our consumption. Besides, the evaporation which is the basic step in the water cycle is due to the sun.
The sun is therefore, the ultimate energy source for earth as we have seen now. There are many other ways in which the sun allows the earth to be an inhabitable place.

The correct answer is option D.

Note:
All the energy forms which we encounter on earth are in some way or the other a result of the solar energy. Even if we think of the petroleum products used for combustion, the life, death and decomposition of those living things were supported by the sun.