The answer to this question is a the estimate the speed of light
The answer is A. wood
because there are three different courts: clay court, grass court, and hard court. wood isn't in there so that would be the answer.
Potential energy due to gravity
<span>An alpine glacier can change the topography of a mountainous area through Glacial Erosion and Glacial Deposition. Glaciers are agents of erosion, it can pick up and carry large rocks and sediments. In the process, a deep cavity or hole can form when the glacier plucks a big rock from where it passed. Glaciers have shaped many Mountain Ranges and have created distinct landforms by its erosion process. In Glacial Deposition, as glaciers melt, it deposits all that it carried and a landform is developed.</span>
Answer: to only change one factor in an experiment or test
