A Level Biology Practice Exam 2025 - Free A Level Biology Practice Questions and Study Guide

The correct choice is systematic error, which is a consistent, predictable error that occurs consistently in the same direction. This type of error typically arises from a flaw in the measurement system, such as equipment calibration or environmental influences, and it leads to a deviation from the true value that remains constant or follows a pattern.

In practical terms, if a scale is not properly zeroed or is improperly calibrated, it will consistently provide measurements that are slightly higher or lower than the actual weight, thus affecting all measurements taken with that scale.

This contrasts with other types of error. For instance, random errors vary unpredictably and are caused by factors that cannot be controlled, such as fluctuations in the environment or slight variations in measurement technique. Human error refers to mistakes made by the person conducting the measurement, and instrumental error relates specifically to faults in the measuring instrument. However, it is systematic error that creates a baseline distortion in measurements across the board, making it the most persistent type in measurement systems.