Answer:
Sugars and phosphates
Explanation:
DNA is deoxyribonucleic acid.
The backbone is based on a repeated pattern of a sugar group (deoxyribose) and a phosphate group.
The image below shows one straightened-out strand of DNA with a backbone of alternating sugars and phosphates.
A is wrong. There is no ribose in DNA.
B is wrong. The nucleic acids A, C, G, and T join one strand of DNA to the other.
C is wrong. There is no RNA in DNA.
Ecologists are concerned with the use of mathematical models and systems analysis for the description of ecological processes and for the sustainable management of resources