Glycogen is a polysaccharide used for energy storage by

The liver and muscles.

Explanation:

Liver and muscles store glucose, in response to insulin hormone, in a form of glycogen for use during starvation period. When glucose is too much in the blood, insulin is secreted by islets cells in the pancreas. Glycogen synthesis is then initiated in liver where it is stored.

Glycogen is a polymer of glucose just like starch in plants. 60% of glucose from glycogen store is used up by the brain as its only source of energy.

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.

b tumor cells have a cell wall instead of a membrane

explanation:

tumor cells different from normal cells because tumor cells have a cell wall instead of a membrane.