Which of the following is a major difference between elliptical galaxies and spiral galaxies? a) elliptical galaxies have almost no gas or dust between the starsb) elliptical galaxies vary more in shape than spiral galaxiesc) spiral galaxies have almost no gas or dust between the starsd) spiral galaxies contain only old stars

- "the choice that is not an indicator of a chemical change is "state of matter changes". more common than not, chemical reactions produce energy in the form of light or heat. along with energy, they also produce a new substance called the product that could be in any state of matter (solid, gas, or liquid)."

b) mutualism

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c. heat could easily travel through the molecules in the air and escape/enter the flask. removing the air slows down the heat transfer.