1.if the same index fossils are found in different rock starta miles apart, what is probably true about the rock layers? 2. what is the longest geologic time period?a shister out. im desperate

Which sentence best expresses the differing opinions of these two book reviews?

Which is an advantage of having memory cells when a pathogen is encountered for a second time. a) the memory cells are what proliferate into clones of cells in response to the binding of an antigen. b) memory cells are vital to the primary immune response in that they immediately recognize pathogens even at the first encounter. c) memory cells are essentially effector cells that are short lived and attack antigens even without having a receptor specific to that antigen. d) it ensures that more lymphocytes with a receptor specific to a particular antigen will be present than in a host that had never encountered that pathogen.

Which of these substances does not protect against invaders in the nonspecific immune response? a. saliva b. mucus c. tears d. urine