FOR PEEPS WHO LIKE ANATOMY AND WHAT NOT
In increasing complexity what makes up an organism?
What are the main structures of the nervous system?
What are the primary functions (jobs) of each of these structures?
How does the nervous system work together with other systems?

Cell
Tissue
Organ
Organ system
Organism

Brain, spinal cord, nerves

The brain controls thought, behavior, emotion, memory, and basic life functions. The brain is also the origin of control over body movement. The spinal cord connects the peripheral nervous system (PNS) to the brain; nerve impulses reaching the spinal cord through sensory neurons are transmitted up into the brain. Nerves primarily involve control and coordination of all parts of the body.

The nervous system interacts with every other organ system. For example the hypothalamus in the brain controls the pituitary gland and tells it when to produce hormones, this shows that the nervous system interacts with the endocrine system.

Hope this helps :)

The answer is a: the eggs have half as many chromosomes as the body cells