Answer:
Topographically SN is classified into:
1. Central SN- made up of the brain and spinal cord
2. Peripheral SN- made up of nerves (31 pairs of spinal nerves, 12 pairs of cranial nerves), nerve plexuses and nerve ganglia
Structural Dpdv
1. Somatic SN \ of relationship life
2. Vegetative SN a) sympathetic- acts in unusual conditions (eg stress, fear)
b) parasympathetic- acts in normal life conditions
Explanation:
If two modern organisms are distantly related in an evolutionary sense, then one should expect that <span>they should share fewer homologous structures than two more closely related organisms.</span>
The answer is 1. Ecosystem.
