Question

which statement best describes both insulin and glucagon?
they both provide structural support, but only insulin is a carbohydrate.
they both store energy, but only glucagon is a carbohydrate.
they are both hormones that regulate blood - sugar levels.
they are both hormones that help fight disease.

Explanation:

Insulin and glucagon are hormones. Insulin lowers blood - sugar levels by promoting glucose uptake by cells. Glucagon raises blood - sugar levels by stimulating the liver to release glucose. They work in opposition to regulate blood - sugar levels.
Neither insulin nor glucagon provides structural support. Insulin is a protein, not a carbohydrate. Glucagon is also a protein. They do not store energy in the way that glycogen (a carbohydrate) stores energy. Hormones that help fight disease are more related to the immune system (e.g., cytokines in some cases), not insulin and glucagon.

Answer:

They are both hormones that regulate blood - sugar levels.