3. A particular radioactive isotope's half-life is 50 million years. What fraction of that isotope will remain if six half-lives go by? How much total time has gone by?

Which statement is true about parks and nature preserves?

Assume that the banner needs to be 18 feet long instead of 15 feet

17. a graduated standard used to evaluate student achievement is called a: a. rubric b. norm-referenced test c. criterion-referenced test d. multiple-choice question e. guessing penalty