People with a genetic variant called the _____gene stand a much higher risk of developing AD

Six-year-old Mark watches his older brother doing his algebra homework. The main reason that Mark will be unable to model his brother's mathematical calculations will be because

a. Mark does not admire his older brother enough. b. Mark will not be reinforced by anyone if he works the math problems correctly. c. Mark is probably unable to reproduce the modeled behavior correctly. d. Mark did not pay enough attention to his brother's modeled behaviors.

What is the smallest detectable difference between two stimuli?

a. ?absolute threshold b. ?doctrine of specific nerve energies c. ?decision threshold d. ?just noticeable difference e. ?threshold of consciousness