“High temperatures___________, and low temperatures _________________.”

Answer

C) kill cells; inhibit cell growth

Explanation

At high temperatures, the fatty acid tails of the phospholipids become less rigid and the cell membrane allows the free movement of proteins in and out of the cell which may end up allowing potential lethal molecules that would kill the cell
Low temperatues will cause the cell to have crystal like molecules inside it, and this would make the cell membrane so rigid that it does not allow any nutrient to enter the cell and thus inhibitng growth