Quick Answer. The function of motor neurons is to release the neurotransmitter acetylcholine, which are released at a junction known as the neuromuscular junction, that bind to postsynaptic receptors, causing the muscle fiber to respond and result into a muscle movement.
The frontal lobe is what really sets us apart from animals, which controls one important aspect of humans: Self awareness. The thinking in terms of I am.. Animals don't do that. (although they DO have sex for pleasure.
Organism obtaining nourishment from or living one another organism (the 'host') for survival and usually harming it and causing disease. Some parasites are independent and some depend entirely on their hosts and separate only when either one of them dies. Human parasites include bacteria, fungi, lice, viruses, and worms.