What is the basic unit of all living things

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.

About how many years does it take for one cycle of surface water to become deep water and then surface water again in the oceans? 101001,000

Jason puts an apple on top of an ice pack in his lunch bag lunch time the temperature of the apple has decreased what happens to the molecules in the apple when the temperature of the apple decreases