Correct Answer: B

Rationale: The correct answer is B: Liters. In the metric system, liters are the base unit for liquid volume. Milliliters, though a metric unit, are a smaller unit of volume and not the base unit. Gallons, on the other hand, are part of the imperial system and not a metric unit for volume. Option D is a duplicate of option B, making it incorrect.

Correct Answer: A

Rationale: To convert milligrams to micrograms, you need to multiply by 1000. Therefore, 0.1 mg is equal to 100 mcg. This conversion is commonly used in medical calculations. Choice B (10 mcg) is incorrect because it would be the conversion from milligrams to micrograms if multiplied by 100, not 10. Choice C (1000 mcg) is incorrect as it would be the conversion from grams to micrograms if multiplied by 1000. Choice D (1 mcg) is incorrect as it represents the original unit without conversion.

Correct Answer: A

Rationale: To convert 0.04 grams to milligrams, you need to multiply by 1000, not 10000. Therefore, 0.04 grams equals 40 milligrams (0.04g * 1000 = 40mg). Choice B, '4 mg,' is incorrect as it reflects the value as if it was in grams. Choice C, '400 mg,' is incorrect as it incorrectly multiplies by 100 instead of 1000. Choice D, '0.4 mg,' is incorrect as it incorrectly moves the decimal point to the right instead of multiplying by 1000.

Correct Answer: A

Rationale: To convert liters to milliliters, you need to multiply by 1000 since there are 1000 milliliters in 1 liter. So, 0.20 liters x 1000 = 200 milliliters. This makes choice A, '200 ml,' the correct answer. Choices B, C, and D are incorrect because they do not reflect the correct conversion factor from liters to milliliters.

Correct Answer: A

Rationale: The mnemonic 'King Hector Died By Drinking Chocolate Milk' aids in recalling metric prefixes in order: kilo-, hecto-, deca-, base (meter, liter, gram), deci-, centi-, milli-. Choice B does not provide a relevant mnemonic for metric conversions. Choices C and D do not offer a helpful phrase for remembering metric prefixes, making them incorrect.