Many plants have evolved mutualistic relationships with nitrogen-fixing bacteria because:
A) The bacteria transform nitrogen into useful forms for the plants; the plants provide carbohydrates
B) The bacteria protect the plant from harmful effects of nitrogen compounds such as ammonia; the plants provide carbohydrates for the bacteria
C) The bacteria utilize nitrogen to produce energy for the plants; the plants provide the source of the nitrogen for the bacteria
D) The bacteria provide natural immunities to the plants; the plants shelter the bacteria from predators
E) There is not a mutualistic relationship between nitrogen-fixing bacteria and plants

Question

Quizplus · Accepted Answer

Nitrogen is essential for plant growth but they cannot utilize atmospheric nitrogen directly. Nitrogen-fixing bacteria form nodules on the roots of certain plants and transform atmospheric nitrogen into useful forms for the plants such as ammonium and nitrate ions. In return, the plants provide carbohydrates and other necessary nutrients for the bacteria. This is a mutualistic relationship as both the plant and bacteria benefit from each other.

Many Plants Have Evolved Mutualistic Relationships with Nitrogen-Fixing Bacteria Because