Final answer:
The diameter of a red blood cell, 8.4 x 10^-6, can be written in standard notation as 0.0000084 meters.
Step-by-step explanation:
The diameter of a red blood cell, which is 8.4 x 10^-6, can be written in standard notation as 0.0000084 meters. To convert from scientific notation to standard notation, move the decimal place to the right according to the power of 10. In this case, the decimal is moved six places to the right.