How do renewable and nonrenewable sources differ? a. renewable resources are artificial b. nonrenewable resources are artificial c. renewable resources replenish within our lifetime d. nonrenewable resources replenish within our lifetime

Which conditions are necessary for natural selection to occur? select all of the answers that apply. a. inheritable adaptations vary among individuals. b. the population size is increasing. c. more individuals are born than can survive. d. fitness varies among individuals. e. the environment changes suddenly and drastically.

Sarah is sitting at the top of the slide in the schools playground. which will increase sarah’s kinetic energy a- an additional child is added to the top of the slide. b- sarah is pushed and moves down the slide. c- sarah climbs down the ladder and off the slide. d- the ladder is moved to the other side of the yard.

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.