If a radiographic substance's half-life is 20 years, how much of a 40 gram sample will be left after 60 years?
A. 5 grams
B. 10 grams
C. 20 grams
D. 30 grams

Read the following quote from the nature conservancy, “the 3 billion people who live in poverty around the world will be hardest hit by climate change. the poor are more dependent on natural resources and have less of an ability to adapt to a changing climate. diseases, declining crop yields, and natural disasters are just a few of the impacts of climate change that could devastate the world’s most vulnerable communities.” from this quote, what group of people is most vulnerable to climate change? those who depend on industrialized nations people who are able to adapt to changing conditions people living in central america people who are living in poverty