Almost everybody has had the feeling of knowing the answer to a question but not being quite able to say it. This is called the tip-of-the-tounge phenomenon, and is a failure of:

The hormone that may indirectly play a role in depression is:

A)serotonin. B)testosterone. C)thyroxin. D)melatonin.

In Piaget's pendulum task, the solution that reveals whether not an individual is in the formal operations stage is ____

a. the length of the string b. the height from which the weight is dropped c. the force with which it is dropped d. the weight of the pendulum