Which of the following are extraneous markings that can interfere with the correct interpretation of waveforms on an EKG tracing?

Glitches refer to temporary malfunctions or errors in the EKG machine or software, which may cause brief interruptions in signal recording. While they can affect the quality of the tracing, they aren't classified as extraneous markings in the same way that artifacts are, which consistently disrupt waveform interpretation.

Smears are typically caused by motion or pressure during the EKG recording, leading to unclear or distorted waveforms. Although they can hinder clarity, smears are specific types of artifacts rather than the broad category of extraneous markings that artifacts represent.

Lines may appear on an EKG tracing due to electrical interference or poor electrode placement, but they do not encompass the full range of extraneous markings. Lines are often a result of specific issues, while artifacts encompass various types of interference that can arise from multiple sources, including environmental factors and equipment malfunction.