Ginkgo biloba is a 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.

placebo control group

Explanation:

In order to determine that a drug has any effect in the body participants of a study are divided into two groups a group which actually receives the treatment and the other group receives a fake treatment. The participants are unaware of which group they belong to.

The fake treatment group is called the placebo control group. If the drug is actually effective then the placebo control group should not shoe the same effects that the treatment group is showing.

Here, the capsule received by group 2 looks like the capsule with the Ginkgo Biloba herb. The participants of group 2 should not show an increased blood flow to the brain. The participants of group 1 should show an increased blood flow to the brain. This would prove that the Ginkgo Biloba increases blood flow to the brain.

could you go a bit more in depth with you question? it's quite hard to understand. as soon as you do that i will be glad to : )