Does this help?
A floodplain (or floodplain) is a generally flat area of land next to a river or stream. It stretches from the banks of the river to the outer edges of the valley. A floodplain consists of two parts. The first is the main channel of the river itself, called the floodway.
Hydrogen atoms are compressed
together by the enormous gravitational force
of the sun, causing them to fuse int a helium atom (which is heavier than
hydrogen), subatomic particles and enormous
release of atomic energy. The attached
picture shows the sequence of the main reaction
at the core of the sun.
The answer is option B "temperature." Greenhouse effect is the process of trapping the suns heat in the lower atmosphere. A increase of greenhouse effect would cause surface temperatures to rise. Which then contributes to global warming because of melting the ice bergs in cooler areas on Earth and causing waters to rise and creating storms. It's not option A because the sun gives off heat or harmful radiant waves which doesn't increase carbon dioxide levels. Wouldn't be option D because it would contribute but it wouldn't happen without a increase of temperature. It also wouldn't be option C because oxygen isn't relevant in this case.
Hope this helps.