The variety of all life forms on Earth.
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).
<span>#1) What ecosystem is described in the paragraph above?
Answer: The ecosystem that is being described in the paragraph above is Tundra. The reason being that the flora and fauna described are from cold climates. Also because the snow leopards are usually found on the tops of mountains, where the climate is cold and windy and rainfall is adequate.
<span>I hope it helps, Regards. </span></span>