Some biologists include a "universal genetic Gene code" as an additional characteristic of life. In all
living things, DNA is the genetic material, and
DNA uses the same code to give the instructions
for making each organism's proteins.
Some living things lack one or two of the
characteristics of life. A mule is the offspring of a
female horse and a male donkey. Mules cannot reproduce and, therefore, mules have
not undergone evolutionary adaptation. However, mules have all the other
characteristics of life, and they are universally accepted as living.
Viruses lack many of the characteristics of life. Viruses don't maintain homeostasis.
They don't have energy metabolism or cellular organization. They don't grow and
develop.

6a. Which characteristics of life are observed in viruses? What are some differences
in how these characteristics of life are observed in viruses vs. bacteria, plants and
animals? (If needed, review the last part of the second video on page 1.)

6b. What do you conclude concerning whether viruses are alive? Is there a clear-cut
distinction between living things and non-living things?