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What is thought to have caused the mass extinction at the end of the cretaceous period?

If the nucleus of a cell was removed the cell wouldn’t be able to make proteins because

Nephrons, the functional unit of kidneys, are responsible for formation of urine. the sentences describe situations that are the result of problems in the urine formation process. for the nephron shown below, match each situation to the step in the urine formation process where the problem lies.