The cell is the basic living unit of the human body—indeed, of all organisms. The human body consists of trillions of cells, each capable of growth, metabolism, response to stimuli, and, with some exceptions, reproduction. read more
carries messages back and forth between the brain and other parts of the body- Brain, spinal cord, or nerves. Connective tissue supports the body and connects all its parts, Blood, fat cartilage, bones, or tendons. read more