Answer:
20 millimeters per second
Explanation:
The speed of the snail can be calculated by dividing the distance traveled by the time taken. In this case, we are given that the snail travels 20mm in 1 second at a consistent speed, so the speed can be calculated as:
Speed = Distance/time = 20mm/1s = 20 mm/s
Therefore, the speed of the snail is 20 millimeters per second.