All of the following statements about evolution are true EXCEPT a. Evolution occurs more rapidly at some times than others.
b. Evolution is directed by changes in the environment.
c. Evolution occurs on the level of single organisms along with populations.
d. Evolution is not always from the simple to the complex but may act in such a way that complex forms give rise to simpler ones.

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.

The response is the basis for vaccination. primary secondary tertiary none of the above

Which skeletal system is represented by the shaded portion of the skeleton? spongy skeleton compact skeleton axial skeleton appendicular skeleton