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.
Through my research I found matching questions with similar answers:
A) macrophages
B) antigens
C) antibodies
D) lymph
The best answer to fill in the blank would be the third option C) Antibodies which in the name anti means against, so since the word anti is the same as against, its a battle between antibodies and invaders, so that's why its C).
A.
conserve energy
The smaller muscle mass of the sloth, means that it needs less energy to work, allowing it to be able to survive on a less diet.
Most of their muscles are concentrated in their upper body, allowing them to be efficient climbers but very slow on the ground.
Foreshadowing means b. hinting at things that will occur later.
