Two-month-old Sheldon is snuggled in his mother's arms. He is quietly looking around, and appears to be simply ‘absorbing' his environment. He is attentive to sounds around him, and is very calm. Sheldon's current state would be described as

a. sleeping

MDMA, or methylenedioxymethamphetamine, is the chemical name for which popular street drug?

A) LSD B) Slippies C) Ecstasy D) Hashish

A group of students was randomly assigned to train their rats on different schedules of reinforcement. Which student's rat will be most likely to extinguish its bar-pressing behavior before the others?

a) Dan, whose rat was trained on a FR 20 schedule b) Sally, whose rat was trained on a FR 1 schedule c) Deana, whose rat was trained on a VI 5 schedule d) Samuel, whose rat was trained on a VR 25 schedule