What does it mean when we say matter is cycles in an ecosystem

What is produced during the krebs cycle? co2, atp, nadh, and fadh2 pyruvate, co2, and atp atp, fadh2, and h2o h2o, adp, and nadh

The reactions that occur in the ribosome, where amino acids are combined to form proteins are anabolic or catabolic?

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.