Define how one goes about selecting a sample for a clinical trial.

If you were given a map of the sensory cortex in the postcentral gyrus of the cerebrum, do you think the map would have more “space” devoted to the regions of the body that have the highest density of sensory receptors, or the regions of the body that have the lowest density of sensory receptors? explain

If someone could do the first couple, just so i can see how it's done that would be great! 20 points. complete a dichotomous key for the 10 leaves on the common leaves sheet. the chart provided here allows for 11 pairs of statements. depending on how you build your dichotomous key, you may or may not need all of them, or you may need to add some.

What is thought to have caused the mass extinction at the end of the cretaceous period?