Final answer:
The concept illustrated by the scenario is language development. Marissa, as a second language learner, is gradually improving her ability to answer questions and express wants in English. Her interactions with English-speaking friends and her weekly progress demonstrate the process of language acquisition and development.
Step-by-step explanation:
The concept illustrated by the scenario is language development. Marissa, as a second language learner, is gradually improving her ability to answer questions and express wants in English. Her interactions with English-speaking friends and her weekly progress demonstrate the process of language acquisition and development.