Given a statement and question, generate the answer to the question such that the answer is contained in the statement.

statement: a wheeled vehicle requires less friction, question: What does a wheeled vehicle require?
less friction

statement: Non-vascular plants play vital roles as producers in aquatic ecosystems., question: What plants play vital roles as producers in aquatic ecosystems?
Non-vascular plants

statement: Cartilaginous fish possess thin skin., question: What type of skin does a fish have?

thin