The _______ group of clinical participants is intentionally given treatments with no active ingredients.

The opioid antagonist naltrexone can prevent heroin from having its normal effect if it is injected

Indicate whether the statement is true or false

A summary of more than 200 studies comparing boys' and girls' temperaments found that girls

A) and boys are equally likely to be shy. B) are more active and they get into more trouble. C) score higher on measures of surgency. D) are better at controlling their emotions.