Which of the following best describes a process that helps a cell maintain homeostasis without requiring energy to be used? 1. Channel proteins provide a passage for molecules to cross the membrane via facilitated diffusion.
2. Membrane carrier proteins help substances enter the cell against a concentration gradient.
3. Pieces of the cell membrane for vesicles circulate around extracellular materials during endocytosis.
4.Protons are pumped out of the cell to create a voltage across the cell membrane.

BY  

Explanation: Maintaining osmotic balance by taking in or releasing water to match the water concentration of the extracellular environment i know it's not 1234 on your list but this is the knowledge i know about your question so i hope it's helps you on the subject.

hydroxyl -oh

alcohols, always polar, can form hydrogen bonds with h2o molecules

carboxyl -cooh  

cargoxylic acids, has acidic properties which is a source of hydrogen ions, found in cells in ionized for with a charge of oh-1

carbonyl > co

ketone if within skeleton, aldehyde if group is at the end of skeleton, k & a may be structural isomers, it determines 2 sugars (ketose & aldose)

amino -nh2

amines, acts as a base, it can pick up h+ ions from surrounding solution, ionized with charge of 1+

methyl ch2

addition to rna/dna affects and gene expression

phosphate -opo3 ²⁻

organic phosphates, contributes to negative charge to, molecule that it is a part of, and potential to react with h20

sulfhydryl -sh

thiols, cross-linking stabilize the protein, and it is structure