The long plateau phase of the cardiac muscle action potential is due to
a. increased membrane permeability to sodium ions.
b. calcium channels remaining open.
c. movement of fewer sodium ions across the cell membrane.
d. a decrease in the amount of calcium diffusing across the membrane. e. increased membrane permeability to potassium ion.

Which of these serves as a reference for comparison during a scientific investigation? a)outcome variable (dependent variable) b) test variable (independent variable) c)control group d)hypothesis

Match the description of each organism to the appropriate category

Drag each tile to the correct box. the body monitors the levels of oxygen in the blood to regulate breathing. isabel is running in a marathon and is near the finish line. she feels out of breath. how will her nervous system work to generate a reaction? arrange the tiles in chronological order. isabel's breathing rate increases. sensory receptors in the arteries detect low oxygen levels. the brain sends signals through motor neurons. sensory neurons generate an impulse. the central nervous system relays an impulse to certain brain regions.