Is confounding a major threat to internal validity

If the president needed to send two members of the cabinet to italy to negotiate a military treaty, the secretary of defense and the secretary of would most likely be sent.

Calculate the iq of a 20 year old who has the mental age of 25

Globalization and technology developments have led to what some individuals have described as "flat world." what is the significance of the flat world concept? what is the impact of the flat world on supply chain requirements and strategies?