Because the climate determains the name and class of it. Say tundra. Its cold, gloomy snowy etc. Those are the characterists AND climate>
They are directly related. The more different trees, the more different birds because not all birds like the same trees:
Some like higher trees to build higher nests, others like lower trees, some like the leaves of some trees useful, some live in the trees that give them fruits, other in trees where many insects go, etc.
Hope it helped!
Answer:
1:2:1 is the genetic crosses
I also think it should be B
