Select the correct answer.
What's the role of oxygen in cellular respiration?
A.
It accepts electrons and keeps the electron transport chain running.
B. It breaks down carbon-based sugar molecules to release energy and forms carbon dioxide.
C.
It combines with hydrogen ions in sugar molecules to release energy and form water.
D.
It supplies electrons to the electron transport chain to keep it running.

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."

the law of original horizontality explains:   why rocks appear in layers. correct answer: b the law suggests that all rock layers are originally laid down (deposited) horizontally and can later be deformed.   the principle is used by geologists to make assumptions about the relative ages of sedimentary rocks.