Membrane proteins are among the most important proteins biologically because they allow cells to communicate with their environments. In humans, they determine whether the immune system recognizes the cell as foreign or not and they are the targets of most . a. Drugs
b. gases
c. sugars
d. water

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.

How does photosynthesis show the conservation of mass and energy?

Physical characteristics of down syndrome