Final answer:
The large squares on ECG paper are equal to 5 millimeters or 0.20 seconds and the correct answer is b) 1 centimeter. This is because each large square spans 5 small squares, which are each 1 millimeter, totaling 1 centimeter.
Step-by-step explanation:
The large squares on ECG (electrocardiogram) paper represent a specific measurement used to accurately interpret heart rhythms and electrical activity. Each large square is equal to 5 millimeters (mm) on the vertical axis, which measures voltage, and 0.20 seconds on the horizontal axis, representing time. Therefore, the correct answer to the student's question is b) 1 centimeter, as there are 10 millimeters in 1 centimeter and each large square is made up of 5 small squares that are each 1 millimeter on a side. This information is critical for healthcare professionals when analyzing ECG results and making diagnostic decisions.