What to stabilize cell membranes and is used by the body to break down steriods

Which animal group is the largest and contains more species from all the other living groups combined? is it mammals or

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 is a function performed by stem cells in the skin a. replacing lost skin cells b. making cells for the intestines c. growing new organs d. differentiating into brain cells plz apex