Correct Answer: D

Rationale: 1 liter is equivalent to 1000 milliliters. This conversion is based on the fact that 1 liter equals 1000 milliliters, a standard metric relationship. Choice A is incorrect because a kilogram is a unit of mass, not volume. Choice B, 1 quart, is a non-metric unit of volume and is not equivalent to 1 liter. Choice C, 1 milliliter, is too small to be equivalent to 1 liter; it takes 1000 milliliters to make up 1 liter.

Correct Answer: A

Rationale: To convert a decimal to a fraction, you can write the decimal as a fraction with the decimal part as the numerator and a power of 10 as the denominator. In this case, 0.75 can be written as 75/100. Simplifying this fraction by dividing both the numerator and denominator by 25 gives you 3/4. Therefore, the correct answer is A. Choice B (7/10), Choice C (15/20), and Choice D (1/2) are incorrect because they do not represent the correct conversion of 0.75 into a fraction.

Correct Answer: B

Rationale: The correct answer is B: 100 cm. 1 meter is equivalent to 100 centimeters. Choice A (10 cm) is incorrect as it represents the conversion of decimeters to centimeters. Choice C (1,000 cm) is incorrect as it represents the conversion of meters to millimeters. Choice D (10,000 cm) is incorrect as it represents the conversion of meters to centimeters with an extra zero.

Correct Answer: B

Rationale: To convert kilometers to meters, you need to multiply by 1,000 since there are 1,000 meters in a kilometer. Therefore, 345 km multiplied by 1,000 equals 345,000 meters. Choice A is incorrect as it incorrectly places the comma. Choice C is incorrect as it adds an extra zero at the end. Choice D is incorrect as it adds an extra zero at the beginning, resulting in an incorrect 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.