What are the three groups of animals in
aristotle's classification system?

Land, Water and Air are the three sub-groups of animals in  Aristotle's classification system. He also classified on basis of red blood cells and without red blood cells.

Aristotle is very popular in ancient Greece and he is very popular in the field of biology and mathematics. He divided the living organisms into two classes called the Plants and the Animals. He divided the animals into two classes – one which contains red blood cells and the other which didn’t contain any red blood cells.

He also noticed that most of the organisms which contained red blood cells are vertebrates i.e they contained a body vertebral column in their back. So they were called as vertebrates and the others were called as invertebrates.

answer; i believe that the correct answer is ; males are hemizygous for the x chromosome;

what statement best describes the difference between the sympathetic and parasympathetic nervous systems?

the sympathetic nervous system prepares the body for intense physical activity and is often referred to as the fight-or-flight response. the parasympathetic nervous system has almost the exact opposite effect and relaxes the body and inhibits or slows many high energy functions.