Please helppp
due soon!!

6. in the dna double helix, how are the two strands of dna held together? a. chemical bonds between base pairs hold the two strands of dna together. b. hydrogen bonds between the base pairs hold the two strands of dna together. c. hydrogen bonds between sugar groups and phosphate groups hold the two strands of dna together. d. chemical bonds between sugar groups and phosphate groups hold the two strands of dna together.

Most of the fossils found in virginia are in the coastal plain, valley, ridge, and appalachian plateau regions, best suggesting that these geographic provinces a) were once covered by seawater. b) are the oldest parts of virginia. c) have a great deal of karst topography. d) have large amounts of sedimentary rock.

Acid rain throughout the northeast united states has lowered the ph of many ponds and lakes. the lowered ph will eventually result in the death of many aquatic animals. compare the map of the u.s. with the ph tolerance range for the organisms listed. based on the tolerances seen here, which aquatic organisms are least likely to survive in the northeastern states?