An explanation of observations or events based on knowledge gained from many observations and investigations is called a

What food can provide the body with a quick source of the energy needed to carry out cell functions (a) whole grain bread (b) ground hamburger (c) vegetable oil (d) whole milk

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.

How does a gymnosperm prevent itself from pollinating the same tree