Heart valves function to heart valves function to control the amount of blood pumped by the heart keep blood moving forward through the heart mix blood thoroughly as it passes through the heart slow blood down as it passes through the heart

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.

What are examples of the plant life and animal life that can be found in each type of terrarium

Crossing over is a method of (blank)?