How did watson and crick determine base pairing?
they analyzed the work of phoebus levene.
they used chargaff's rule to fit the bases together.
they broke the hydrogen bond.
they observed the pairing under a microscope.

What is the first step in a life cycle of a plant reproduce sexually

Use this diagram of an animal cell to answer the question. where does the first stage of cellular respiration occur? w x y z

Up until 1938, paleontologists accepted the idea that coelacanths (an ancient fish) went extinct at the time that they last appear in the fossil record, about 80 million years ago. but in 1938, a live coelacanth was discovered off the coast of south africa that was compared to the fossil record and found to be the same species what goal of science does this discovery represent