One difference is the number of double bonds in the fatty acid chain
The answer is that they do not live on or in the body of a host.
Yes
None of them produce their own energy
It consists of skin, hair, nails, and glands. The skin protects the body from the environment on the outside. It also functions to retain body fluids, protect against disease, eliminate waste products, and regulate body temperature. It also helps store fat and water.
Hope This Helps!