Which reaction occurs most rapidly at standard conditions? A.
H2(g) + I2(s) 2HI(g)
B.
Cu(s) + S(s) CuS(s)
C.
C6H12O6(s) + 6O2(g) 6CO2(g) + 6H2O(g)
D.
5C2O42-(aq) + 2MnO4- + 16H+(aq) 10CO2(g) + 2Mn2+(aq) + 2H2O(1)
E.
Ag+(aq) + I- AgI2(s)

in scientific notation, the value of the  speed of light in a vacuum

  will be written as 2.995 * 10^8. when this value is represented in the form of

  a * 10^b, then, a = 2.995 and b = 8.

the value of the speed of light in a vacuum given above can also be rounded up to approximately 300000000. in this case, the scientific notation will be written as 3 *10^8.

it is the most commonly accepted one

the answer is b because, investigating whether another species of moth also drinks tears might be interesting, but it would not directly explain why this species of moth does.

to explain why this species of moth drinks tears, the scientist could ask: "what nutrients that moths need are in elephant tears? "

the scientist could experiment with moth repellent or oter ways to keep the moths away, but that would not answer his original question.