Cells are also the basic functioning unit of life. Cells are often organized into organs to create higher levels of complexity and function. Living things have the ability to take energy from their environment and change it from one form to another. This energy is usually used to facilitate their growth and reproduction. We call the process that allows for this facilitation metabolism .
Organisms tend to be homeostatic .
In other words, they regulate their bodies and other internal structures to certain normal parameters. Living creatures respond to stimuli. Cues in their environment cause them to react through behavior, metabolism, and physiological change. Living things reproduce themselves by making copies of themselves. Reproduction can either be sexual or asexual .