The hottest atmospheric layer is the:

The correct answer is: C. Thermosphere.

The thermosphere is the outermost layer of Earth’s atmosphere. It is located above the mesosphere and extends from about 80 to 600 kilometers (50 to 370 miles) above Earth’s surface. The thermosphere is the hottest layer of Earth’s atmosphere, with temperatures reaching up to 2,500 degrees Celsius (4,500 degrees Fahrenheit). The high temperatures in the thermosphere are caused by the absorption of ultraviolet radiation from the sun.

The thermosphere is very thin, with an average density of only about 100 molecules per cubic centimeter. The low density of the thermosphere means that there is very little air resistance in this layer. This allows satellites and other spacecraft to orbit Earth without burning up.

The thermosphere is also home to the aurora borealis, also known as the northern lights, and the aurora australis, also known as the southern lights. These beautiful light displays are caused by the collision of charged particles from the sun with atoms and molecules in the upper atmosphere.

The thermosphere is a very important part of Earth’s atmosphere. It protects us from harmful radiation from the sun and helps to regulate Earth’s climate.

The other options are incorrect because:

• The stratosphere is the second layer of Earth’s atmosphere. It is located above the troposphere and below the mesosphere. The stratosphere is characterized by a decrease in temperature with increasing altitude. This is due to the presence of ozone, which absorbs ultraviolet radiation from the sun.
• The mesosphere is the third layer of Earth’s atmosphere. It is located above the stratosphere and below the thermosphere. The mesosphere is characterized by an increase in temperature with increasing altitude. This is due to the lack of ozone, which allows ultraviolet radiation from the sun to heat the atmosphere.
• The troposphere is the lowest layer of Earth’s atmosphere. It is located from the surface of Earth to about 12 kilometers (7.5 miles) above sea level. The troposphere is characterized by a decrease in temperature with increasing altitude. This is due to the fact that the air in the troposphere is heated by the Earth’s surface.