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.

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

answer; /// i believe that the correct answer is ( monophasic ); ethinyl estradiol- ethynodiol diacetate is a monophasic oral contraceptive agent; ///

because of

lunar landing mission. apollo 11 was the first manned mission to land on the moon. the first steps by humans on another planetary body were taken by neil armstrong and buzz aldrin on july 20, 1969. the astronauts also returned to earth the first samples from another planetary body.

explanation: