Need explanation and answer plzzz

Sally and sue were investigating the topic of friction in science. they used a small car and a ramp as seen in the picture to test what they were learning. they knew that they slipped easily on waxed floors but not on carpet, so they decided to change the material on the surface of the ramp to see what happened. they planned to use glass, carpet, aluminum foil, and sandpaper and run the car down the ramp over each surface. what would be the best research question to guide the girls' experiment? a) does the amount of surface area affect the friction on the moving car? b) will the car travel fastest on the glass surface? c) how does the angle of the ramp affect the speed of the car? d)do rougher surfaces tend to create more friction than smooth surfaces?

Hurry where is the majority of earth's water found? o glaciers o oceans ground o rivers and lakes

In this assignment, you will analyze an example of speciation by researching the finches of the galapagos islands. then you will answer questions to construct explanations and draw conclusions based on the information you gather. someone plz !