Christian Andreas Doppler's study of waves led him to conclude that as a wave source moves away from an observer, the frequency of the wave seems to decrease. If the source moves toward an observer, wave frequency increases. This
conclusion has been MOST useful to scientists who are -
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answer: d. a cme increases the amount of energy in the solar wind

explanation:

coronal mass ejections, also called cmes, are large clouds of plasma and magnetic field that erupt from the sun. only when the cloud is aimed at earth will the cme hit earth and therefore cause impacts. high-speed solar wind streams come from areas on the sun known as coronal holes.

depends on what you mean by "group." for order, it would be coleoptera (beetles). for class, it would be insecta (insects). for phylum, it would be the arthropoda (animals with jointed exoskeletons).

explanation:

a longitudinal wave moves energy that is to the direction of the wave’s movement. - true