Scientific notation is a way of expressing numbers that are either very large or very small in a concise format. In scientific notation, a number is represented as a product of a number (between 1 and 10) and a power of 10.
For instance, the number 5,000 can be expressed as 5.0 x 103. Similarly, 0.001 can be written as 1.0 x 10-3. To determine if an expression is in scientific notation, look for two key components: first, a single non-zero digit to the left of the decimal point, and second, an exponent on 10 that can be either positive or negative.
So, in your given choices, check to see if any meet these criteria to identify which expression is indeed in scientific notation.