How could sand dunes be held in place to prevent them from drifting onto a parking

When analyzing tree rings, what do scientists assume a thin ring indicates?

Food webs - transferring energy and matter from one level to another. here you see four food webs. one or more are incorrect. which food web(s) show the correct sequence of organisms, from start to top level consumer? a) a b) d c) c d) a and d

Explain how sequences of amino acids in proteins can be used to reveal relationships among organisms.