When something happens between relative parts to keep a system functioning, this is called a/an blank interaction

Mucous membranes.. a. cover or line external surface of body. b. line internal body surfaces that are in contact with the environment. c. produce antibodies to combat infection. d. secrete sweat, which has antibacterial enzymes.

Which of the following is not considered a lymph node function? to house immune cells to transport lymph to filter blood to fight infection

What is the proper way to determine that someone is unresponsive before administering cpr