Which of the following is not a limbic system structure? hippocampus hypothalamus substantia nigra amygdala

substantia nigra

Explanation:

The Limbic system is a complex set of brain structures that can be seen on both sides of the thalamus. It supports a variety of functions including emotion, behavioral activities,motivation, memory e.t.c.  It composition entails the hypothalamus, the hippocampus and the amygdala.

The hypothalamus which is  located below the thalamus (i.e hypo means "under") helps to regulates thirst, body temperature, and sexual behavior, and helps maintain a steady (homeostatic) internal state of the body of an organism.

Hippocampus is the centre of memory.

Amygdala (an almond-shape set of neurons) play a key role in the processing of emotions.

On the other hand, The substantia nigra is a basal ganglia structure that can be seen in the midbrain. The substantia nigra plays a vital role in reward and movement.  This area of the brain  sends signals down the spinal cord to control the muscles of the body.

explanation:

b,bacteria convert nitrates

into nitrogen gas.

d,plants and animals take in

and use nitrogen compounds.

e,bacteria break down waste    

products and return nitrogen  

to the soil.

a,bacteria convert atmospheric

nitrogen to ammonia.

c,bacteria convert ammonia

to nitrites and nitrates.

condensation. good luck!