Question

The tundra is a harsh environment.
Only the toughest plants and animal can survive.
Joining words:
And.
Or,
But,
So

Answer 1

The tundra is a harsh envioroment so only the toughest plants and animals can survive.

Answer 2

Answer:

The tundra is harsh environment so, Only the toughest plants and animals can survive.

Explanation

Just read them i guess and see which makes more since