Correct Answer: A

Rationale: To convert milligrams to micrograms, you need to multiply by 1000 because there are 1000 micrograms in 1 milligram. Therefore, 0.15 mg is equal to 150 mcg. Choice B (15 mcg) is incorrect as it represents the conversion of 0.015 mg to mcg. Choice C (1.5 mcg) is incorrect as it represents the conversion of 0.0015 mg to mcg. Choice D (1500 mcg) is incorrect as it represents the conversion of 1.5 mg to mcg. So, the correct answer is 150 mcg, a conversion often used in medical dosing.

Correct Answer: B

Rationale: The correct answer is B: 30 ml. 1 ounce is equivalent to 30 milliliters. This conversion is a common one in many contexts involving liquid measurements. Choice A (20 ml), Choice C (40 ml), and Choice D (50 ml) are incorrect conversions and do not represent the accurate conversion between ounces and milliliters.

Correct Answer: A

Rationale: A femtometer is equivalent to 10^-15 meters. The prefix 'femto-' signifies a factor of one quadrillionth (10^-15), making choice A the correct answer. Choice B (10^-9 meters) represents a nanometer, not a femtometer. Choice C (10^-12 meters) corresponds to a picometer, not a femtometer. Choice D (10^-18 meters) is even smaller than a femtometer and refers to an attometer, not a femtometer.

Correct Answer: C

Rationale: To convert kilometers to meters, you need to multiply by 1000 because there are 1000 meters in 1 kilometer. Therefore, 5 kilometers x 1000 = 5000 meters. Choice A (50 meters) is incorrect because it underestimates the conversion. Choice B (500 meters) is incorrect as it also underestimates the conversion. Choice D (0.5 meters) is incorrect as it incorrectly represents the conversion as less than a kilometer.

Correct Answer: B

Rationale: To convert liters to milliliters, you need to multiply by 1000, not 10000. Therefore, 0.2 liters equals 200 ml (0.2 x 1000 = 200 ml). Choice A, 20 ml, is incorrect because it's the result of multiplying by 10 instead of 1000. Choice C, 2 ml, is incorrect as it's the result of ignoring the decimal point. Choice D, 2000 ml, is incorrect because it's the result of multiplying by 10000.