Which is one way scientists indicate how precise and accurate their experimental measurements are? a. they keep accurate, honest records. b. they make sure their experiments can be repeated. c. they use significant figures in their measurements. d. they record small samples of data.

These are two different questions, as precision and accuracy are different things.

Precision is described by the number of significant figures in a measured value.  This would suggest that C is the answer.

Accuracy is a measure of how close a measured value is to the actual thing it's measuring.  A and B would be the answer to this question.

D isn't the answer to anything, as multiple samples are needed.

The answer is c. 320 g