How is the number 3.91 x 10 -4 expressed in regular numbers?
a. 0.391
b. 0.391
c. 0.0391
d. 0.000391

Answer : The correct option is, (D) 0.000391

Answer : The correct option is, (D) 0.000391Explanation :

Scientific notation : It is defined as the way or representation of expressing the number that are too big or too small that is written in the decimal form.

That means always written in the power of 10 form.

For example : 700 is written as, As we are given that the value of Avogadro’s number is,

This number is written in regular number as, 0.000391

Therefore, the correct option is, (D) 0.000391

um i think it might be a car?

what is the question here. i think you messed up.