Acid rain is formed when certain gases from factories mix with water vapour in the air. Which of the following is a long-term "hidden" effect of acid rain on a forest?
A) It washes away all the leaves so the trees look like it is winter.
B) It changes the soil chemistry, dissolving vital nutrients that trees need to grow.
C) It makes the forest floor too slippery for animals to walk on.
D) It causes the trees to grow much faster than normal, making them weak.