8. how do nitrogen-fixing bacteria cycle nitrogen through ecosystems? (1)
a. they release nitrogen into the atmosphere when they replicate their dna .
b. they convert sunlight into chemical energy which is then stored in the nitrogen.
c. they convert ammonia from animal feces and urine into forms that plants can use.
d. they capture nitrogen from the atmosphere and convert it into forms that plants can use

What is the main difference between the central nervous system (cns) and the peripheral nervous system (pns)? .the cns involves the brain and spinal cord, and the pns involves the body nerves. the cns involves the body nerves, and the pns involves the brain and spinal cord. the cns involves sensory neurons, and the pns involves motor neurons. the cns involves motor neurons, and the pns involves sensory neurons.