The doppler effect indicates that the frequency of energy (sound or light) waves when an object is approaching and when an object is moving away.

Explanation:

According to Doppler effect:

1) When the source of the frequency is approaching, The apparent frequency heard by the observer will be more than that of the actual frequency.

2) When the source of the frequency is moving away, The apparent frequency heard by the observer will be less than that of the actual frequency.

f = Real frequency of the source

f' = apparent frequency heard by the observer

v = velocity of the sound

= velocity of the source

c.) polymerase chain reaction

- "unlike the original dna fingerprinting method, dna profiling does not use restriction enzymes to cut the dna. instead it uses the polymerase chain reaction (pcr)? to produce many copies of specific str sequences. pcr is an automated procedure that generates lots of copies of a specific sequence of dna."