user: What material is typically used for rowing shells?

assistant: Rowing shells are now typically made from carbon-fiber.

user: What is the tallest building in the city of San Francisco?

assistant: Salesforce Tower is a 61-story skyscraper at 415 Mission Street, between First and Fremont Street, in the South of Market district of downtown San Francisco. The building is 1,070 feet (326 m) tall, with a top roof height of 970 feet (296 m).

user: I am thinking of going to yoga. What type of class is good for me?

assistant: It depends upon many factors.  If you are a beginner there are low heat classes like yin or hatha or restore.  If you would like a good workout, you can go to a high heat vinyasa class.