Earth Systems and Basic Astronomy - Class X

Sun is the ultimate source of energy. The radiation of sun helps to warm the earth. Changing the temperature of earth forms different season. Plants directly depend on the sun to prepare their own by photosynthesis. Sun provides energy in different form solar energy. Thus, the correct option is C.

The sun is called the ultimate source of energy because it is the source of almost all energies of the earth. Plants convert light energy from the sun into chemical energy (food) by the process of photosynthesis. Animals eat plants and use that same chemical energy for all their activities.

Scientific estimates of the number of stars in the observable universe are typically in the range of 10^22 to 10^24.

A typical galaxy like the Milky Way is estimated to contain roughly 100 billion stars, which is 100,000 million.

Neptune is the eighth and farthest known planet from the Sun in our solar system.

Inferior planets are those whose orbits lie within the orbit of the Earth, specifically Mercury and Venus.

Jupiter is the largest planet in our solar system, with a mass more than twice that of all the other planets combined.

The concentration of ozone in the troposphere is typically very low, often cited around 0.05 ppm in clean or background conditions.

According to modern theories of chemical evolution and Oparin-Haldane's hypothesis, the early atmosphere of the earth was reducing, containing water vapor, hydrogen, ammonia, and methane, but free oxygen was absent.

Exobiology, also known as astrobiology, is the study of the origin, evolution, and distribution of life in the universe, including the impact of extra-terrestrial environments on life.