A student builds a model to show how pollutants move through an ecosystem when the student sprays water onto the model, red color appears in the cloth and
in the water in the middle layer of marbles. Which part of the model represents
pollutants used by humans
Red powdered paint
Layer of sand
Thick cloth
Marbles

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

Development of new communities in disturbed environments, such as a burned or a clear cut forest, is called

Does masterbation affect height growth or loss of growth hormone?