Answer:
Though they are often debated, there are eight main characteristics that define a cell as living.
The first is genetic code. All living things contain DNA, which is like the instruction manual for life. DNA is contained in each cell, and passed from parent to offspring.
The second is growth and development. Whether by creating more cells or creating more organelles within the cell, all living things grow and develop.
The third characteristic is reproduction. Reproduction can be sexual or asexual, but in the case of single cells, it is asexual.
The fourth characteristic is response. All living things, including cells, react to external stimuli, such as temperature or salinity.
The fifth characteristic is homeostasis. Homeostasis is the condition by which living things maintain a stable internal environment in the midst of an ever-changing external environment.
The last three characteristics go hand in hand, and are sometimes combined, but in my mind they are distinctly separate.
Sixth is consumption, which is taking in food and other materials. A cell specifically takes in molecules such as water or glucose during consumption.
Seventh is metabolism, which is using materials consumed in order to create energy. Living cells use enzymes to break down materials to produce ATP (adenosine triphosphate), which is usable energy.
Finally, all living cells undergo excretion in some form. Some examples in cells include exocytosis and osmosis.
These 8 characteristics, though often controversial, determine a cell as living.