Which molecules do cells need to get from outside the body in order to function properly?

Water, carbon dioxide, and oxygen are among the few simple molecules that can cross the cell membrane by diffusion (or a type of diffusion known as osmosis ). Diffusion is one principle method of movement of substances within cells, as well as the method for essential small molecules to cross the cell membrane.

Explanation:

1. cold turkey (no outside ). about 90% of people who try to quit smoking do it without outside support -- no aids, therapy, or medicine. although most people try to quit this way, it's not the most successful method. only about 5% to 7% are able to quit on their own.

2. behavioral therapy. this involves working with a counselor to find ways not to smoke. together, you'll find your triggers (such as emotions or situations that make you want to smoke) and make a plan to get through the cravings.

3. nicotine replacement therapy. there are several types, including nicotine gum, patches, inhalers, sprays, and lozenges. they work by giving you nicotine without the use of tobacco. you may be more likely to quit with nicotine replacement therapy, but it works best when you use it with behavioral therapy and lots of support from friends and family. and remember that the goal is to end your addiction to nicotine, not simply to quit using tobacco.

explanation:

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