The tissue layers of blood vessels from outer layer to inner layer are:

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.

Milk production during breastfeeding is increased by the suckling of a newborn from his mother's nipple. this type of feedback mechanism best describes a positive or negative

Which macromolecule catalyzes chemical reactions this be considered enzyme chemical reactions thus he considering enzymes