Answer:
Explanation: Pollution is the introduction of contaminants into the natural environment that cause adverse change. Pollution can take the form of chemical substances or energy, such as noise, heat, or light. Pollutants, the components of pollution, can be either foreign substances/energies or naturally occurring contaminants.
The answer is - Sunspots.
Sunspots are dark in appearance, but only on a visible light, and this is due to the fact that they are much cooler than the surrounding areas, but that doesn't mean by any means that the sunspots are cool, on contrary, they are very hot too. Sunspots actually are storms that appear in the lower atmosphere of the sun.
I think you know the answer, but it is 4.
