Which of these best describes a laser? 7 of 12 QUESTIONS
O A beam of light containing electromagnetic waves of only one wavelength
A beam of sound waves that can be used to heat or cook food
O A device that uses radio waves to detect the location and speed of objects
O A device used to convert light energy to electrical energy
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Match each medication with its description.

What does spontaneous generation mean?

Crinoids, also known as sea lilies, appear to be sea plants but are not plants at all. crinoids are an echinoderm species which uses anchoring structures called holdfasts to attach themselves to the sea floor. crinoids were most abundant in pennsylvania during the mississippian period, which ranged from 375 to 320 million years ago. fossils of the crinoids shows that during most of this time pennsylvania was that provided favorable conditions for crinoid growth. a) glacial terrain b) a dry and sandy plain c) mostly mountain ranges d) covered by warm, shallow seas