Please help I really would appreciate it

What links the two strands in a dna helix together in the middle? a. phosphate groups b. sugar rings bonded together c. proteins d. bases with hydrogen bonds

The images show the wings of a bat and a bee. from this evidence, what can you conclude about the evolutionary relationship between these organisms? a. the wing structures of the bat and the bee are different, indicating they didn’t inherit wings from a common ancestor. b. the wing structures of the bat and the bee are different, indicating they inherited wings from a common ancestor. c. the functions of bat wings and bee wings are the same, indicating they obtained wings from a common ancestor. d. the functions of bat wings and bee wings are different, indicating they didn’t obtain wings from a common ancestor.

How does friction with the atmosphere affect the speed of an artificial satellite