Which of the following is true of pure substances and mixtures? (check all that apply.) pure substances are made up of mixtures. pure substances are separated by physical means. mixtures can be separated by physical means. a pure substance is heterogeneous. a mixture is made of one substance. mixtures are made up of more than one component.

How is ribosomal rna useful as a molecular clock? a. a large portion of the dna ring is not vital to structure or function, allowing it to accumulate neutral mutations. b. its rate of mutation increases over time as organisms continue to evolve and differentiate from each other. c. a slow mutation rate makes it useful for determining evolutionary relationships between ancient species. d. it is only found in select organisms, making it easier to compare relationships between species that have it.

Which of these transport mechanisms moves glucose from the blood into a cell? active transport diffusion facilitated diffusion osmosis

Write the balanced chemical equation forphotosynthesis.