A. umbilical cord is the answer
An organism that lives in or on another organism and gets its food from or at the expense of its host
Answer:So yes,humans and other mammals (like dogs) have same immune system. Differences may occur in the protein structures, but they all come in same family and work similarly like humans.
Explanation: Are animal immune systems different from humans? - Quora
https://www.quora.com/Are-animal-immune-systems-different-from-humans
