Light strikes a beautiful white perch under water. this light is reflected back to your eyes allowing you to see the fish. as the light left the water it speed causing the light to bend away from the normal.

The answer is: Light strikes a beautiful white perch under water. This light is reflected back to your eyes allowing you to see the fish. As the light left the water it changes speed causing the light to bend away from the normal.
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(got answer from https://quizlet.com/5474123/chapter-13-light-flash-cards/ if you need more help)

The velocity would be 2 

The population of unionid mussels decreased after zebra mussels were introduced. zebra mussels competed with the unionid mussels for food. the zebra mussels were able to displace the unionid mussels, allowing the zebra mussel population to increase  over the years. the unionid mussel population decreased because  of lack of food.