If an isotope's half life is 2 months, and it starts with 240 grams. How many half life's does it take to only have 15 grams left? A. 2
B. 4
C. 6

Compare and contrast region e in the illustration above with region d. describe the physical characteristics of each region.

How do the evolutionary chart and the video support the claim that all living things are made up of cells?

Karen is a forensic scientist whose purpose is to identify and evaluate physical evidence. which of the following tasks does she perform? a. reporting results of scientific analysis b. interviewing suspects c. questioning witnesses d. preparing victims for burial