One function of the carbohydrate macromolecule is to store energy. which other macromolecule also functions in storing energy?

Explanation:

Lipids are the macro-molecules used to store energy in our body. They have the ability to store energy more efficiently and are called long-term energy storage.  

They can store twice as much energy as other molecules. They contain nine Kcal of energy per gram a compared to proteins and carbohydrates which only produce four kcal per gram. They are present in our body in the form of fat and are insoluble in water.

they deliver oxygen to the blood

i think a) betsy can donate only blood to mark is correct because, mark and betsy have the same blood type. whereas nobody else has b+ blood so betsy can't donate to them.