molecule. 1  Chemistry, Physics. the smallest physical unit of an element or compound, consisting of one or more like atoms in an element and two or more different atoms in a compound. 2  Chemistry. a quantity of a substance, the weight of which, measured in any chosen unit, is numerically equal to the molecular weight; gram molecule.
When I do crunches my neck starts to tighten up and it makes me have to rest before doing another set of crunches.
For bronchitis or sinus infection, you could also eat spicy foods to help loosen and thin mucus thereby giving your body an easier way of expelling it.With bronchitis, the mucus is loosened in the chest area while mucus in the head area is loosened in sinus infections.or bronchitis or sinus infection, you could also eat spicy foods to help loosen and thin mucus thereby giving your body an easier way of expelling it.