Index fossils are most useful because they .

A. occur in all rock types
B. occur over a brief time interval
C. occur over a small geographic area
D. occur over a long period of time are difficult to identify

Look at the data above. provide an explanation for europe’s projected population decrease by the year 2050. (i'm doing this for future kids) the answer is : the percentage of people over the age of 65 and under the age of 15 in europe is currently the same at 16% each. therefore, the majority of the population is between the ages of 16 and 64. in forty years from now, in 2050, a greater percentage of the population will be over the age of 65. europe also has a relatively long life expectancy of 75 years. this, combined with a low birth rate means that by 2050 europe’s population will actually be less than it is today.