What is the function of the immune system?

Which mantle is under the crust the upper mantle or the lower mantle i think it's upper let me know if i'm right

Ineed to get this test done which of the following statements is correct in hour our immune system responds to a potential pathogen? a.) the skin will be the first line of defense, and then the many phagocytes in the bloodstream will attempt to consume the possible pathogen. b.) b cells will start reading the antigen code immediately and call t cells to assist in destroying the pathogen. c.) the adapted immune system will call on the innate immune system to destroy the pathogen. d.) the t-cells in the adapted immune systems are the first to recognize the pathogen

What are some common health, safety, and sanitation hazards in many of today's restaurants? what foodborne illnesses commonly occur from poor sanitation in the kitchen? how can you ensure that your kitchen is safe? ( need )