An element has a half-life of 30 years. If 20 mg of this element decays over a period of 90 years, how many mg of this element would remain?

What best describes lactic acid fermentation?

Variety of living organisms; includes genetic, species, and ecological types.

Pentane with molecular formula c5h12, exists in three isomeric forms. one shows linear carbon chains, another has one -ch3 groups present on the third carbon atom, and the third has two -ch3 groups present on the second carbon atom. what types of isomers are these? a. geometric isomers b. structural isomers c. halotropic isomers