Correct Answer: A

Rationale: 'kg' stands for kilogram, the unit of mass equal to 1,000 grams. In the metric system, 'kg' specifically represents the unit of mass, making 'kilogram' the correct choice. The other choices, 'keg,' 'kroner,' and 'kraken,' do not represent the standard unit of mass in the metric system and are therefore incorrect.

Correct Answer: A

Rationale: To convert milligrams to micrograms, you need to multiply by 1000 because there are 1000 micrograms in a milligram. Therefore, 0.025 mg x 1000 = 25 mcg. This means that the correct answer is A, 25 mcg. Choice B, 250 mcg, is incorrect because it incorrectly multiplies by 10 instead of 1000. Choice C, 2.5 mcg, is incorrect as it inaccurately divides the value by 10. Choice D, 0.25 mcg, is also incorrect as it divides the value by 100 instead of multiplying by 1000.

Correct Answer: C

Rationale: The correct answer is C: 1,000 grams. The metric system follows a logical conversion where 1 kilogram is equal to 1,000 grams. This conversion is a fundamental concept in understanding units of measurement. Choices A, B, and D are incorrect because they do not accurately reflect the conversion between kilograms and grams. Option A (10 grams) is incorrect as it represents 1/100th of the correct conversion. Option B (100 grams) is also incorrect as it represents 1/10th of the correct conversion. Option D (10,000 grams) is significantly higher than the actual conversion, making it incorrect. Understanding these basic unit conversions is essential for various fields where precise measurements are necessary.

Correct Answer: A

Rationale: The correct answer is A: 10^-9 meters. 1 nanometer (nm) is equivalent to 10^-9 meters. This conversion is commonly used in various scientific fields, including nanotechnology, to represent extremely small lengths. Choice B, 10^-6 meters, is incorrect as it represents a micrometer, not a nanometer. Choice C, 10^-12 meters, is incorrect as it would be a picometer, which is smaller than a nanometer. Choice D, 10^-15 meters, is incorrect as it would be a femtometer, much smaller than a nanometer.

Correct Answer: C

Rationale: The correct answer is C: 0.13 inches. When converting decimals to inches, the value remains the same. Choice A, 0.013 inches, represents a smaller value than 0.13 inches as it has an extra zero. Choice B, 1.3 inches, is incorrect as it is a larger value than 0.13 inches. Choice D, 13 inches, is significantly larger than 0.13 inches, making it an incorrect conversion.