When we inhale oxygen, it is eventually transferred from the respiratory system to the circulatory system. the is where gas exchange takes place between the lungs and the blood.
a. alveoli
b. bronchi
c. vena cava
d. bronchioles?

Match the following terms describing electrical events with the correct phases of the cardiac cycle. the ventricular muscle cells depolarize at the start of this phase. during this phase, na+ entry through the funny channels causes the pacemaker potential of sa nodal cells to gradually become less negative until it reaches threshold. the ventricular muscle cells repolarize right before this phase. the cytosolic concentration of calcium in the contractile cells of the ventricle is highest during this phase. a. isovolumetric relaxation b. ventricular ejection c. isovolumetric contraction d. ventricular filling

The leopard frog and the pickerel frog are two closely related species. in areas where their ranges overlap, the frogs will remain separate species if they

Will mark brainliest. (20 points) many have pigments structures known as eyespots that detect direction of light. a. b. archaebacteria c. protists d. none of the above