WILL MARK BRAINLIEST
Which internal structure is an adaptation that provided organisms with the function
to perfor gas exchange on land?
Gills
Lungs
Hollow bones
Chambered heart

Probably lungs- gills are for water creatures, hollow bones dont have connection with the respiratory system, and chambered hearts also dont deal with the respiratory system

Explanation:

the sugar-phosphate backbone forms the structural framework of nucleic acids, including dna and rna. this backbone is composed of alternating sugar and phosphate groups, and defines directionality of the molecule.