In the pioneer stage of primary succession, small flowering annual plants?

Where in the body can you find chemoreceptors? a. on the skin and ears, to detect pressure, touch, motion, and sound b. on the retina, to detect a single photon of light c. on the skin, to detect temperature or specific chemicals d. on the tongue and in the nose, to detect taste or odor

What function does the limb sever in each animal? how are the limb bones of the four animals similar? based on these similarities what can be inferred about the evolution of the four animals.

What are the student's observations and inferences before he starts his investigation?