To determine the size of the needle, remember that the higher the gauge number, the ___________ needle bore.

The correct understanding lies in the fact that the gauge of a needle inversely correlates with its diameter. Higher gauge numbers indicate a smaller needle bore, meaning that as the gauge number increases, the actual size of the needle decreases. This is a commonly used standard in medical and laboratory settings, where needles often range from very fine (high gauge) to thicker (low gauge). Hence, selecting "smaller" accurately reflects this inverse relationship, making it the appropriate choice.

In contrast, terms such as "larger," "thicker," and "weaker" do not accurately represent the relationship between needle gauge and size. Higher gauge does not denote a larger or thicker needle, nor does it imply any kind of weakness in terms of performance; it's primarily a measurement of physical size. Understanding this concept is crucial for accurately selecting needles for various applications in healthcare and science.