Name the Three Threats to Internal Validity That Can Occur

question 8

Essay

Name the three threats to internal validity that can occur in studies regardless of the use of a comparison group. Why doesn't a comparison group help in these cases?

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Definitions:

Allantois

An extraembryonic membrane of reptiles, birds, and mammals that stores the embryo’s nitrogenous wastes; most of the allantois is detached at hatching or birth.

Nitrogenous Wastes

Metabolic waste compounds that contain nitrogen, commonly produced by the breakdown of proteins and nucleic acids in organisms.

Umbilical Cord

A flexible cord-like structure containing blood vessels, connecting the fetus to the placenta during pregnancy.

Allantois

An embryonic membrane in reptiles, birds, and mammals that is involved in respiration and excretion.