Question

What is an orginasim that feeds off of a living host?

Answer 1

Parasites that live in the body are called endoparasites. An example of an endoparasite is a hookworm that lives in the hosts gut. 

Answer 2

Surrounding every nucleus is a double-layered membrane called the nuclear membrane or nuclear envelope. This membrane separates the nucleoplasm, or fluid inside the nucleus, from the cytoplasm, or fluid outside the nucleus.