To study osmosis, a student placed a thin potato slice in a salt solution. the slice became soft and shriveled. then, he placed the shriveled slice in water. the slice regained its original shape. based on the observations, which of these statements is correct? a) the slice regained its shape because salt moved into the potato. b) the potato slice shriveled because water moved from the salt solution into the slice. c) the potato slice shriveled because water moved out of the slice into the salt solution. eliminate d) the slice regained its shape because the concentration of salt inside and outside the slice became equal.

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?

Which greenhouse gas is emitted when burn fossil fuels for energy? a.nitrogen b.oxygen c.carbon dioxide d.helium

What is the primary function of the nervous system?