Oxygen in the lungs leaves the air sacs and enters the blood veins capillaries

When analyzing tree rings, what do scientists assume a thin ring indicates?

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 food could be transported in a galvanized metal container?