Sometimes a cell needs to move molecules from an area of low concentration to an area of high concentration (against the flow). How does a cell do this?

What came first egg or chicken? and is tomato a vegetable or a fruit?

Indica el nombre y la fucion de los vasos sanguineos que entran y salen de los riñones

What do all macromolecules have in common with each other? oa. they all are formed from the same elements.ob. they all have major roles in cell membranesoc. they all act as catalysts in the body.od. they all have peptide bonds between carbon atoms.