Why did andrew jackson hold his hat up? what does it symbolize?

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?

Martin, a 32-year-old human relations administrator at a university, believes that all professors over age 50 are incapable of learning the new educational technologies and are content to keep presenting their same "tired, boring" lectures. he often expresses these views to other administrators and does not encourage any of the "older" faculty members to attend professional development meetings related to new teaching approaches nor does he suggest that the university send them to any of the technology conferences. martin is exhibiting

Nami conducts an investigation on plants. she places a grow light on a timer to give the plants different amounts of light to see if this would affect their growth. in this investigation, the amount of light is the .