Halley's comet has an extremely elliptical orbit around the sun, with an eccentricity of 0.967. its average orbital radius is 17.8 au, and it was last observed in 1986. use kepler’s third law to calculate when halley's comet will appear next. (note: the answer you obtain is based on averaged data and is an approximation.)

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?

Select all that apply. why are common names not a good reference to a species? common names can be in different languages common names vary with location common names vary with culture common names vary with species color

Which statement describes characteristics of planarians? a they live in oceans, are parasites, and reproduce only sexually. b they live in fresh water, are parasites, and reproduce only asexually. c they live in oceans, are free living, and reproduce sexually and asexually. d they live in fresh water, are free living, and reproduce sexually and asexually.