Which statement best describes an active solar energy system? (3 points) Heat is absorbed in the floors and walls, seeping heat into the home.
Solar energy from the south side of the home is utilized for heating.
Skylights contribute to heat loss with solar energy.
Water-filled tubes carry heat for heating the home.

The second one

Explanation:

image result for how many calories of energy will 20 grams of carbohydrates provide in one gram provides 4 calories

consuming the right balance of protein, carbohydrates and fat can you maintain a healthy weight and optimize your energy levels. protein and carbohydrates both contain 4 calories per gram, while fat provides 9 calories per gram.

during the process of dna replication, brdu can replace thymidine and incorporate into the newly synthesized dna, cell proliferation thus can be reflected in the extent of brdu incorporation.