Select the correct answer from each drop-down menu. The pair of triangles that are congruent by the ASA criterion is . The pair of triangles that are congruent by the SAS criterion is .

The weight of a radioactive isotope was 96 grams at the start of an experiment. after one hour, the weight of the isotope was half of its initial weight. after two hours, the weight of the isotope was half of its weight the previous hour. if this pattern continues, which of the following graphs represents the weight of the radioactive isotope over time? a. graph w b. graph x c. graph y d. graph z