Which of the following expressions is written in scientific notation? a. 0.3 • 10^4 b. 2 • 10^-5 c. 10 • 10^3 d. 12 • 10^-3

b.

Step-by-step explanation:

1. By definition, an expression in scientific notation has the following form:

Where a is a number greater or equal to 1 and less than 10.

2. Therefore, as you can see, the expression given in the options shown in the problem above that has the form  , where 2 is a number greater or equal to 1 and less than 10.

3. Then, the answer is the option b.