The valve seat performs two functions: it provides a seal for the valve in the combustion chamber, and it provides a cool surface to carry heat away from the valve. most valves use a seating angle. a. 30 b. 60 c. 45 d. 15

In automobile machines, the valve seat usually has a 45° angle. This is the optimum angle opening for the valve seat to maintain a straight lever head. Other designs include a 30° angle cut behind the valve seat for smoother transition. The answer is C. 45°.

A. is considered an abiotic factor