Figure 4.4 shows three wave crests moving to the right. When the crest of wave A

period = 10.00 s, frequency = 0.1 Hz

Explanation:

The period of the wave T, is the time it takes the wave to move between two successive crests. Since wave A passes point P at 0.00 seconds and  wave B passes point P at 10.00 seconds, it completes a cycle of the wave and the period, T is 10.00s - 0.00 s = 10.00 s.

So, the period of the wave is T = 10.00 s

The frequency, f = 1/T = 1/10.00 s = 0.1 Hz

Nucleic acids

Explanation:

DNA is a nucleic acid which contains the instructions for making proteins