Which social class is quickly disappearing from modern economies?

The chart shows four articles read by the students in a science class

Explain how tectonic plate movement creates geological events and features.

Psychologists studying infant memory want to determine at what age babies can remember specific events. an experimenter uses several puppets to demonstrate a series of actions while the infant watches. after a delay, the experimenter records how many of the actions the child imitates when playing with the puppets. what is the dependent variable?