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

The cellular plasma membrane is selectively permeable, which means some materials move through it while others cannot. the movement of materials into and out of the cell is called membrane transport. this activity will you identify the different mechanisms of membrane transport