I guess the answer is to protect against because the primary function of the lymphatic system is to transport lymph, a fluid containing infection-fighting white blood cells, throughout the body.
B. is the correct answer. It makes sense too because vaccines are usually inserted in a vein, which is where the bloodstream is. With all of this medicine in your body, the virus will come into the body, the body will recognize what the virus is, sending out the antibodies from the vaccine into the bloodstream and all around, then the virus is dead. :)
D) It is based on the position of rock layers.
It's number four, i remember it in the lesson. FLVS right?
