Which statements identify what astronomers currently know and think will happen with our universe? Check all that apply. The big bang produced dark energy, which accounts for some of the energy needed to expand the universe.
The vastness of space may contain a type of matter known as “dark matter.”
The universe is currently shrinking at a rapid rate.
The universe is currently expanding at an accelerating rate.
The big bang theory explains all the energy and matter discovered by scientists.

Why was the sample heated in step 5? describe the chemical principles involved in the reasoning behind this step?

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?

Why did rutherford say that bombarding atoms with particles was like "playing with marbles" what