If the center atom has four single bonds around it, what type of molecular geometry is present

Although respiratory organs vary across different organisms, they all contain respiratory surfaces that have a large surface area and are extremely thin. explain why having an extremely thin respiratory surface with a large surface area is advantageous for the process of gas exchange

In which reaction is precipitation occurring?

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