bout one foot every 9000 years. If erosion continues at the same rate, the United States will be pletely down to sea level in about 23 million years. Р(1). Flowing water gradually makes its channel ______. РA. narrower РB. deeperРC. wider РD. both B and CР(2). The average height of the United States above sea level ___. РA. is being raised each yearРB. remains constantРC. will reach sea level in 9000 yearsРD. is being lowered little by littleР(3). Erosion by water results in _______. РA. wearing down the soilРB. building up landРC. enriching the soilРD. both B and CР(4). Implied but not stated: ________РA. Millions of years ago the United States was higher than it is nowРB. Great amounts of land are moved to the sea by riversРC. The water that sinks into the earth also reaches the oceanРD.
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