When did tea replace coffee as the dominant stimulant drink in Great Britain?

Piaget has provided us with the ______ context of children's concepts, whereas Vygotsky has provided us with the ______ context

cognitive; behaviorist empirical; experimental individual; social social; individual

Gabe has noticed lately that his grandmother isn't as cheerful as she used to be. Even among family and friends, she tends to look sad. Her once epic appetite is gone too; she just tends to pick at her plate. Which of the following neurotransmitters may be causing these changes in Gabe's grandmother?

a. acetylcholine b. serotonin c. cortisol d. dopamine