Scientists use a variety of tools to learn about the history of the earth, evolution, environmental change, and its effects. Which type of evidence is most affected by human error (and thus less reliable)? fossils and the fossil record
rock core samples and strata
mathematical and computer models
areas of impact

5) these are organisms where the genetic material is not bound by a nucleus. they are usually unicellular.

Which of the following systems in absorbing oxygen and releases carbon dioxide

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?