Kidneys play a major role in the human excretory system by filtering what fluid?

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.

Explain how paleontologists use trilobite fossils as index fossils for various geologic time periods.

Which of the following describes the difference in stimuli required to detect a difference between the stimuli? a. just noticeableb. signal detectionc. subliminald. top down