20. How does the USDA define a concentrated animal feeding operation (CAFO)? A. A CAFO is defined as an AFO with over 1,000 animal units kept for over 45 days a year

B. A CAFO is defined as an AFO with over 1,000 animal units kept for the majority of a year.

C. A CAFO is defined as an AFO with over 1,000 animals of any size kept for over 45 days a year.

D. A CAFO is defined as an AFO with over 1,000 animals of any size kept for the majority of a year

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.