Scientists know a lot about ancient Earth's climate because of clues that remain in rocks, ice, trees, corals, and fossils. These clues tell us that the
Earth's climate has changed many times over the years. There have been times when most of the planet was covered in ice, and there have also been
much warmer periods. Over at least the last 650,000 years, temperatures and carbon dioxide levels in the atmosphere have increased and decreased in
a cyclical pattern

Which of the following statements is true? a. the main cause for speciation is an increase in gene flow. b. organisms that reproduce asexually are not considered part of a species. c. on a tree of life diagram, speciation is shown by the merging of two different lineages. d.the size of the geographic area inhabited by a population can cause speciation.

Control of the body is accomplished by which of the following body systems? nervous system and circulatory system endocrine and repertory system circulatory and respiratory systems nervous system and endocrine systems

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?