Acertain radioactive nucleus undergoes exponential decay with a half-life of 10 days. the fraction of the initial sample that remains after 2 half lives?

Several kinds of bears are found on earth. most bears are brown or black, but one type of bear, the polar bear, is white. what process led to this difference in fur color? explain your answer.

Areaction in which products can react to re-form reactants is

According to the passage, which of these is true about gray water systems? a) gray water systems use plants that require less water. eliminate b) gray water systems require the use of less fossil fuels. c) gray water systems reduce the amount of fresh water used. d) gray water systems reduce the amount water used by shower heads.