Characteristics of Life Characteristics of life include living
things that are made of cells or cell products, use energy,
respond to changes in the environment, maintain homeostasis and
reproduce with similar offspring. These characteristics define
whether something is living or not. When people start studying
what is life, my students often say "why do we need to bother
having all these definitions for life because itâs kind of duh
obvious what is a life." And that seems true in the beginning
but scientists actually had to sit there and try to narrow it
down because originally when people did study life, they
ascribed life to a lot of things that we now know aren't alive.
For example, they used to think that fire was alive. And we know
now itâs not. So what are the characteristics of life? Well one,
weâve discovered that all life on this planet is made up of
cells or products of cells. For example, my body is made up of
gazzillions of cells. Skin cells, muscle cells, nerve cells,
blood cells et cetera but t