Explain how it is possible to have thousands of different proteins when there are only 20 different amino acids?

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.

Explain how scientists use geologic time to determine the age of landforms.

which is an effect of short-term environmental changes? a) adaptation b) speciation c) extinction d) death (5 points)