Problem: What are the most important words?
An overcooked hotdog in a bun sits beside a soda and condiments.
Answer: bun, hotdog, sit

Problem: What are the most important words?
people buying religious souvenirs in souvenir shop
Answer: buy, shop, souvenir

Problem: What are the most important words?
ecology the study of how organisms interact with their environment
Answer:
ecology, environment, interact, organism, study