Hi Mr. Wood this is Jenny from Per. 3,
Here are my answers for the questions:
I think the factors that cause the area to be tundra are the temperature, the location, and the weather.
With a warmer climate the weather might change, the amount of precipitation might change, and also the tundra might be able to support different types of plants and animals.
The tundra has no large trees because there isn't enough precipitation, so the trees can't grow.
-Jenny