On average, a 4- or 5-year-old child has an attention span of ____

The __________ speeds up the passage of electrical messages by acting as an insulator of the neuronal signal

A) blood-brain barrier B) terminal button C) myelin D) synaptic vesicles

Which of the following statements is most true regarding home-based research?

A) External validity may be high, but internal validity can be compromised. B) Typically, internal validity is higher than in laboratory research. C) It is typically easier and quicker to obtain data in this context than in laboratory research. D) It's best to conduct home visits alone, bringing more than one person could be viewed as too invasive by the family.