Identify the threats to internal validity related to participants in a study. Choose the correct answer from the options given below.

The participant related threats among these options are selection, history, and attrition.

Testing threat stems from the measurement procedure rather than from the participants themselves.

Selection threat arises from pre existing differences between groups of participants.

History threat arises from outside events affecting participants during the study.

Attrition threat arises when participants leave the study unevenly.

Randomisation and equivalent control groups help counter these threats.