Which of the following species has demonstrated the ability to communicate meaningfully with each other and with humans by the use of gestures, sounds or symbols?

Since 1990 the number of individuals simply choosing to refer to themselves as "American" has:

a. decreased significantly. b. decreased marginally. c. stayed the same. d. increased marginally.

A researcher who is testing the cognitive functioning of middle-aged adults would find which of the following to be true of her subjects regarding well-rehearsed, familiar tasks?

A) They would have difficulty performing them B) They will show gradual decrements C) They perceive impaired performance D) They maintain or gain in skill