What are the pros and cons of quadrat sampling?

Dwarf galaxies are select one: a. relatively rare. b. not very bright c. mostly spiral shaped. d. none of these.

Each pair of clay balls represents two planetesimals. if each planetesimal is composed of the same material and is separated he the same distance, which pair experiences the frayed gravitational attraction?

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.