I believe the answer is B. I think it's B because I just studied this subject in school and it sounds best
Answer:
The correct answer is D
Explanation:
During the 20th century, there was an increasing interest in the environment. The impact of human activity on the environment has been observed locally since centuries. Pollution of canals and chimneys in crowded urban areas etc were all causes of concern.
However, with a better understanding of our earth and increase in Medical knowledge of the 20th century, we could observe how our activities were having a global impact on the ozone layer and the melting ice caps.
Evidence was also provided on how human health was affected by this. The use of fossil fuels was not only directly damaging to the atmosphere, it was also dangerous for humans e.g. carbon monoxide produced by car emissions.
Tropical places are hot because the humidity coming from the moisture of the plants and water are heated by the sun on the top layer of the tropical zone. The climate varies little in rain forest. There are five layers in the tropic trees so it's so thick that barely any light come through. This is also why vines grow up the trees so they can reach the sunlight to get nutrients. Also, the tropics are near the equator and that also causes the heat. The polars are cold because they barely get any sun heat to melt the snow or warm it up. The polars are melting due to certain chemicals and gasses in the atmosphere. also known as global warming. Hope that was helpful!
The renewable energy source is Hydroelectricity.
