What describes the speed of a planet traveling in an elliptical orbit around the Sun? A. constant B. fastest when closest to the Sun C. slowest when closest to the Sun D. fastest when closest to the Moon

newton's first law of motion

that tool is called an altimeter which measures your altitude which can be used to tell which atmosphere you are currently in, including the stratosphere.

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luster is not a good characteristic to use by itself because luster is the property of minerals that indicates how much the surface of a mineral reflects light. the luster of a mineral is affected by the brilliance of the light used to observe the mineral surface.