Final answer:
The Correct option is a). To find the mass of a substance in grams from micrograms, multiply the number of micrograms by 1 x 10^-6. Therefore, 8 x 10^9 micrograms is equal to 8000 grams.
Step-by-step explanation:
The mass of the substance in grams can be found by converting the given mass from micrograms to grams. We use the conversion factor that one microgram is equal to 1 x 10^-6 grams. To convert 8 x 10^9 micrograms to grams, we multiply the number of micrograms by the conversion factor:
Mass in grams = mass in micrograms x 1 x 10^-6 g
Mass in grams = 8 x 10^9 x 1 x 10^-6 g
Mass in grams = 8 x 10^3 g
Mass in grams = 8000 grams
Therefore, the mass of the substance is 8000 grams.