Correct Answer: D

Rationale: The correct answer is D: 1,000 mg. This is because 1 gram is equivalent to 1,000 milligrams. To convert grams to milligrams, you multiply by 1,000. Choices A, B, and C are incorrect. Choice A (1 mg) is the smallest unit, and it would take 1,000 of these to make 1 gram. Choice B (10 mg) is also too small, as it would require 100 of these to equal 1 gram. Choice C (100 mg) is closer, but it still falls short of the correct conversion, which is 1,000 mg in 1 gram.

Correct Answer: B

Rationale: The correct answer is B: 2000 pounds. A ton is equivalent to 2000 pounds. This is a standard conversion in the imperial system of measurement. Choice A, 1000 pounds, is incorrect as it represents half a ton. Choice C, 1500 pounds, and Choice D, 2500 pounds, are also incorrect as they do not match the correct conversion of 1 ton to 2000 pounds.

Correct Answer: D

Rationale: The correct answer is D: Exact Equivalent. The expression 1 inch = 2.54 cm is a direct and precise conversion between inches and centimeters, making it an exact equivalent. It is not related to the Law of Conservation of Units (A) as this principle pertains to the conservation of physical quantities in a system. The International Yard (B) is a unit of measurement, but it is not the term for the given expression. Similarly, while the conversion factor in the expression is standard, it is specifically an exact equivalent and not just a general standard conversion factor (C). Therefore, D is the most appropriate term to describe this specific conversion relationship.

Correct Answer: A

Rationale: To convert 0.26 to a fraction, we write it as 26/100. To simplify this fraction, we divide both the numerator and the denominator by their greatest common divisor, which is 2 in this case. Dividing 26 and 100 by 2 results in 13/50. Therefore, 0.26 as a fraction in simplest form is 13/50. Choice B (26/100) is the original form of the decimal, not simplified. Choice C (26/1000) is incorrect as it doesn't match the decimal representation. Choice D (1/4) is not the equivalent fraction for 0.26.

Correct Answer: B

Rationale: To convert centimeters to kilometers, you need to divide by 100,000 since there are 100,000 centimeters in a kilometer. Therefore, 35.4 cm · 100,000 = 0.000354 km. Choice A (0.00354 km) is incorrect as it represents dividing by 10,000, not 100,000. Choice C (0.00345 km) is incorrect as the last digit is different from the correct answer. Choice D (0.0345 km) is incorrect as it represents dividing by 1,000, not by 100,000.