Which level of organization is characterized by a group of cells that work together to perform a common function? organ
tissue
organ system
organism

Acceleration is a direct result of a.) balanced forces b.) unbalanced forces c.) gravity d.) velocity

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.

Diagram of the evolution of land plants?