What is a precursor?
a. a substance that is recycled through the liver and intestines
b. a sign or symptom of a clinical vitamin deficiency disorder
c. a substance that is used to synthesize another compound
d. a conditionally essential vitamin
e. a sign or symptom of a subclinical vitamin deficiency disorder

A precursor is c) a substance that is used to synthesize another compound.

Explanation:

A precursor in chemistry is a compound that participates in a chemical reaction to obtain another compound. Also, they could be predecessors of other compounds in a metabolic pathway such as tryptophan and serotonin; tryptophan is the metabolic precursor for serotonin.

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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