Correct Answer: Infrared waves are largely absorbed by water vapor that is concentrated in the lower atmosphere.

Explanation:

1. “The total amount of insolation received at the equator is roughly about 10 times that received at the poles.”
   Incorrect.
   While there is a significant difference in insolation between the equator and the poles due to the angle of incidence of solar radiation, it is not as extreme as 10 times. The actual difference is much smaller, generally ranging from 2 to 3 times.
2. “Infrared rays constitute roughly two-thirds of insolation.”
   Incorrect.
   Infrared rays are part of the electromagnetic spectrum, but they only constitute a small portion of the incoming solar radiation (insolation). The majority of insolation consists of visible light and ultraviolet radiation.
3. “Infrared waves are largely absorbed by water vapor that is concentrated in the lower atmosphere.”
   Correct.
   Infrared waves, which are long-wavelength radiation, are absorbed by greenhouse gases such as water vapor, carbon dioxide, and methane. Water vapor, concentrated in the lower atmosphere (troposphere), plays a major role in absorbing and trapping infrared radiation, contributing to the greenhouse effect.
4. “Infrared waves are a part of the visible spectrum of electromagnetic waves of solar radiation.”
   Incorrect.
   Infrared waves are not part of the visible spectrum. The visible spectrum includes wavelengths between 400-700 nanometers, whereas infrared waves are longer than this range and are not visible to the human eye.