What neurotransmitter is released from most varicosities in the sympathetic division?

After fertilization, which type of cellular division is responsible for the growth and development of a complex, multicellular organism?

An organ system consists of a group of organs that performs specific functions necessary for the survival of an organism. humans have eleven different organ systems: integumentary, skeletal, muscular, nervous, endocrine, circulatory, lymphatic, respiratory, digestive, urinary, and reproductive. discuss the function of neurons, the brain and the spinal cord within the human nervous system while explaining the interrelationship of each organ.

There are fewer than 100 naturally occurring elements in the universe, but there are millions of different unified substances. explain how this can be true.