Final answer:
In proper scientific notation, there must be only one non-zero digit in front of the decimal, and any number including zeros in front of the multiplication sign are significant, depending on their placement and context.
Step-by-step explanation:
The question asks how many numbers can be in front of the decimal if the number is in correct scientific notation. The answer is C) One. Scientific notation requires that there be only a single non-zero digit before the decimal point. The coefficient should be greater than or equal to 1 and less than 10. For example, converting 637.8 to scientific notation would be 6.378 × 10², and converting 0.0479 would yield 4.79 × 10⁻².
When considering significant figures, all numbers before the multiplication sign in scientific notation are significant. If zeros are present, they are significant only if they occur between other significant figures or are trailing zeros after a decimal point that are part of the measurement.
In cases where ambiguity exists, zeros can be clarified as significant by using scientific notation, such as in the difference between 8.666 × 10⁶ (four significant figures) and 8.6660 × 10⁶ (five significant figures). Scientific notation helps clearly define which zeros are placeholders and which are part of measured values that are significant.