An engineer constructs a prototype from wood. Which of the following is the best tool for the engineer to use to make the prototype's surface smooth?

sandpaper

Which of these organisms is a producer in a marine ecosystem?

algae

At a weightlifting competition, two competitors lifted the same weight to the same height. The second competitor accomplished the lift 2 seconds faster than the first competitor. This demonstrated that the second competitor had more
power than the first.