20 points 1. Some students used vinegar to dissolve away the shells of three eggs
and used these eggs as models of human red blood cells. The students
observed the changes in the eggs when they were placed in different
solutions. Which statement best describes the role of the cell membrane
in this model? *

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

When a human or animal consumes food, the carbon in that food is most likely to be converted into which of the following elements? a. carbon remains carbon b. nitrogen c. oxygen d. hydrogen

Which of the following terms describes all of the non-living components of an ecosystem