How do you know which equation (law) to use when plugging in the numbers?

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

Which material burns faster? metal aluminum

What atom has the largest atomic radius