What do organs combine to form? a. cells b. organisms c. organ systems d. tissues

Explanation:

Organ systems, such as the circulatory system, are made up of many organs working together. For example, the circulatory system is made up of the heart, veins, and lungs.

carbohydrates: (starches and sugars) composed of carbon, hydrogen, and oxygen.

lipids: (fats, oils, and waxes) are made of carbon and hydrogen atoms.

nucleic acids: contain hydrogen, oxygen, nitrogen, carbon, and phosphorus. they are polymers of nucleotides. a nucleotide has three parts, a 5-carbon sugar, a phosphate     (-po⬇️4) group, and a nitrogenous base.

proteins: made up of nitrogen, carbon, hydrogen, and oxygen. they are polymers of amino acids.

the correct answer is:

a population changes in response to a change in the environment.