Explain facilitated diffusion. Where is this happening in the cell? Is the substance moving up or down a concentration gradient? When will this process stop?

Buuy which of the following did you include in your response? organs perform specific functions in the body to keep it alive. organelles perform specific functions in cells to keep them alive. done

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.

Acceleration is a direct result of a.) balanced forces b.) unbalanced forces c.) gravity d.) velocity