How many hours does it take the earth to rotate once on its axis

What element is able to combine with itself and hydrogen to form large molecules ?

When the cell concentrates potassium within, against the natural tendency of matter, it is performing a.passive diffusion b.facilitated diffusion c.active transport d.pinocytosis

Did the vinegar diffuse all the way to the center of any of the cubes? if so, which ones? what does this tell you about surface area-to-volume ratio and the diffusion rate?