The diagram below shows four objects in the solar system which have equal masses. Which of these pairs of objects exerts the least gravitational force on each other? (3 points)
Object 1 and Object 3
Object 4 and Object 3
Object 1 and Object 2
Object 4 and Object 2

If the concentration of phosphate in the cytosol is 2.0 mm and the concentration of phosphate in the surrounding fluid is 0.1 mm, how could the cell increase the concentration of phosphate in the cytosol? a) passive transportb) diffusionc) active transportd) osmosise) facilitated diffusion