Question

choose the molecule that is described by each phrase. energy used during long activities: lipid complete main source of energy: glycogen lipid protein done

Explanation:

Carbohydrates (such as glucose) are the main source of energy for the body. Glycogen is a storage form of glucose in animals. Lipids are used for long - term energy storage and energy during long activities. Proteins are mainly for building and repairing tissues, although they can be used for energy in extreme cases. Since the question is about the main source of energy, and among the given options (glycogen, lipid, protein), glycogen is a form of stored carbohydrate. But if we consider the general concept (assuming the first blank was a hint for energy - related molecules), the main source of energy (in a more general sense, not just from the given options' limited scope) is carbohydrate. However, if we have to choose from the given options, glycogen (as a storage carbohydrate) is the closest as it can be broken down into glucose (the immediate energy source). Lipid is for long - term/long - activity energy and protein is not the main energy source.

Answer:

glycogen