Cells use to get energy only when carbohydrates are not available? a. nucleic acids b. lipids c. hormones d. proteins

The right answer is Lipids.

Just as glucose degradation allows energy production in the cell, in the form of ATP, degradation of fatty acids (lipids) allows cells to obtain the energy necessary for their survival. This degradation occurs in the mitochondria, according to a set of reactions grouped under the term of Lynen's helix (or beta-oxidation of fatty acids).

The degradation of lipids thus allows the synthesis of a usable energy by the cell (ATP).

answer: a. a gene that causes a specific trait.

the relative standard reduction potential of the half-cell in which reduction occurs; more positive than the other half-cell. reduction is a chemical process in which electrons are added to an atom or an ion; it always occurs accompanied by oxidation of the reducing agent.