Question: What’s the difference between swimming in the pool and swimming in the sea?
Analysis

1. Discuss the differences in environment, such as controlled conditions in a pool versus natural conditions in the sea. 2. Mention differences in water conditions, like saltwater versus chlorinated water, and the presence of waves or currents in the sea. 3. Consider safety aspects, such as lifeguards in pools and potential hazards in the sea.

Synonyms
Try these synonyms instead of repeating the question:
  1. difference→distinction; contrast
  2. swimming→bathing; floating
  3. pool→swimming pool; indoor pool
  4. sea→ocean; open water