What is the difference between direct and indirect energy transfer in trophic levels? Please help!

How does friction with the atmosphere affect the speed of an artificial satellite

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.

Draw the structure of dna nucleotide with adenine as nitrogenous base