Final answer:
The whale might eat 6.3 x 10^4 pounds of plankton in a week, which is equivalent to 630,000 pounds in standard notation.
Step-by-step explanation:
The correct answer is D. 630,000 pounds.
When we write 6.3 x10^4 in standard notation, we move the decimal point 4 places to the right, which gives us 63,000.
However, the question asks for the weight of the whale in pounds, which is 6.3 x10^4 pounds. So, we need to move the decimal point 4 places to the right again, resulting in 630,000 pounds.