Question

Many plants have evolved mutualistic relationships with nitrogen-fixing bacteria because: select one:
a. the bacteria utilize nitrogen to produce energy for the plants; the plants provide the source of the nitrogen for the bacteria
b. the bacteria transform nitrogen into useful forms for the plants; the plants provide carbohydrates
c. the bacteria protect the plant from harmful effects of nitrogen compounds such as ammonia; the plants provide carbohydrates for the bacteria
d. there is not a mutualistic relationship between nitrogen-fixing bacteria and plants
e. the bacteria provide natural immunities to the plants; the plants shelter the bacteria from predators

Answer 1

I believe the answer is b. the bacteria transform nitrogen into useful forms for the plants; the plants provide carbohydrates

Plants need nitrogen from the soil to do photosynthesis and produce carbohydrate. The amount of nitrogen is limited but bacteria can synthesis it, giving the plant ingredients that they need. In return, the plant provide carbohydrate to the bacteria. This is a mutualistic symbiosis because they both gain profit for the cooperation.

Answer 2

Answer is b. b. the bacteria transform nitrogen into useful forms for the plants; the plants provide carbohydrates.

In the root nodules of many legumes, symbiotic nitrogen-fixing bacteria called Rhizobia reside. The relationship between a host legume and the Rhizobia is symbiotic or mutualistic in which both partners get benefit.  Once the Rhizobia have established themselves in the root nodule, the plant provides carbohydrates (food) to the bacteria, and in return the Rhizobia provide ammonia for the formation of amino acids and nucleotides.