Which of the following events occurs during - metaphase? A) Spindle fibers shorten.
B) A cell begins to divide in two.
C) Nuclear membrane breaks down.
D) Chromosomes line up at the equator.

B. A cell begins to divide in 2

Explanation:

in metaphase a cell is condensing into chromosomes so it splits

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 form of energy changes and the total energy increases0l