Solar eclipses occur about twice a year. but seeing a total solar eclipse is often described as a "once in a lifetime" experience. why is it so rare to experience a total solar eclipse?
total solar eclipses only occur once or twice a century
. the width of the moon's shadow is very narrow, so a particular area is very unlikely to lie along the path of totality during the eclipse.
total solar eclipses usually occur in late winter, when clouds are most likely to block the view.
if you aren't paying attention at the time, its very easy not to notice a total solar eclipse.

The correct answer is option B.

B) The width of the Moon's shadow is very narrow, so a particular area is very unlikely to lie along the path of totality during the eclipse.

Total solar eclipse is a very rare event to occur, This is called once in a lifetime experience because it is very difficult for the moon to cover the sun at a partial way, hence its very rare.

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 correct answer is c   with the systems