Which describes a constant in an experiment?
a. the variable changed by the experimenter
b. the quantity that must remain the same
d. the variable that changes in response to the experiment
d. the statement that is worded to test the experiment

What is the main difference between the central nervous system (cns) and the peripheral nervous system (pns)? .the cns involves the brain and spinal cord, and the pns involves the body nerves. the cns involves the body nerves, and the pns involves the brain and spinal cord. the cns involves sensory neurons, and the pns involves motor neurons. the cns involves motor neurons, and the pns involves sensory neurons.