Some bacteria live in the roots of plants like soybeans and peas. what is the role of these bacteria in the nitrogen cycle?

a. to absorb nitrogen-containing compounds from the soil
b. to release free nitrogen into the atmosphere
c. to break down nitrogen-containing compounds in dead organisms
d. to convert free nitrogen into usable nitrogen

The correct answer is (d) To convert free nitrogen into usable nitrogen.

The nitrogen present in the soil is not directly used by the bacteria. It can be used only when the nitrogen is converted into usable form. These bacteria convert  atmospheric nitrogen into ammonia, then nitrite which is then converted into nitrate. This nitrate is used by the roots of the plants like soybeans and peas. This is the role of bacteria present in the roots of the plant to convert atmospheric nitrogen into usable form that can be used by plants.

after receiving a stimus, the sensory receptors send(s) signals to the appropriate area of the body.  

the must be sensory neurons.  

hope its .