Ginkgo Biloba Is an Herb That Is Thought to Increase

Multiple Choice

Ginkgo biloba is an herb that is thought to increase blood flow in the brain and enhance memory processes. In a carefully controlled study investigating this claim, young adults were assigned to one of three groups. Those in group 1 took a capsule containing 120 milligrams of ginkgo biloba once a day. Those in group 2 took a capsule that looked identical but was a fake. Those in group 3 did not take any capsules. The participants assigned to group 2 constituted the _____ in this study.

A) dependent variable
B) placebo control group
C) extraneous group
D) out-of-control group