Which best describe the structure of dna?
a.) purine backbones with pyrimidines on the inside.
b.) base backbones with sugar on the inside.
c.) sugar-phosphate backbones with bases on the inside.
d.) a backbone of bases with phosphate groups on the outside.

Why do you think the puppy litter was all dark-haired?

Which of the following is a difference between active transport and facilitated diffusion? view available hint(s)which of the following is a difference between active transport and facilitated diffusion? facilitated diffusion can move solutes against a concentration gradient, and active transport cannot.active transport involves transport proteins, and facilitated diffusion does not.facilitated diffusion involves transport proteins, and active transport does not.active transport requires the expenditure of cellular energy, and facilitated diffusion does not.

Which of the following is the source of energy for photosynthesis? a.) glucose b.) chlorophyll c.) carbon dioxide d.) sunlight