Question

1. what is a measurement in science?

a guess about the size of an object.
a way to classify objects based on size.
a qualitative observation without numbers.
a quantitative description that includes a number and a unit.

1. what is accuracy in measurements?

how close measurements are to each other.
how close a measurement is to the true value.
a measurement without any uncertainty.
the number of digits in a measurement.

1. what is precision in measurements?

the number of significant figures in a measurement.
how close a series of measurements are to one another.
the exact value of a measurement.
how close a measurement is to the true value.

Explanation:

Question 1

• Option A: A guess is not a measurement. Eliminate.
• Option B: Classification based on size is not measurement. Eliminate.
• Option C: Qualitative observations without numbers are not measurements (measurements are quantitative). Eliminate.
• Option D: Measurements in science are quantitative, including a number (magnitude) and a unit (scale), so this is correct.

• Option A: This describes precision (closeness of measurements to each other), not accuracy. Eliminate.
• Option B: Accuracy is how close a measurement is to the true (accepted) value. This matches.
• Option C: All measurements have uncertainty. Eliminate.
• Option D: The number of digits relates to significant figures, not accuracy. Eliminate.

• Option A: Significant figures relate to precision but the option's description is incorrect (precision is not just the number of sig figs). Eliminate.
• Option B: Precision is the closeness of multiple measurements to each other. This matches.
• Option C: Measurements have uncertainty, so no "exact" value. Eliminate.
• Option D: This describes accuracy, not precision. Eliminate.

Answer:

D. A quantitative description that includes a number and a unit.

Question 2