Which of the following processes is directly responsible for these changes in the concentrations of sodium and potassium ions inside and outside the nerve cell?

✿   this landform has a high elevation and a high relief

✿   this landform is a mountain

he forelimbs below belong to four species that descended in a direct line from the ancestral mammal shown above. of the four descendants shown, which species most likely appeared earliest in evolutionary history?

blood enters the heart through two large veins, the inferior and superior vena cava, emptying oxygen-poor blood from the body into the right atrium of the heart. as the ventricle contracts, blood leaves the heart through the pulmonic valve, into the pulmonary artery and to the lungs where it is oxygenated.