Can’t figure out number 31 plz helppp

This is world science btw

What major factors play a role in global warming? 1. human activity and normal climate conditions 2. natural factors and human activity 3. normal climate conditions and abnormal human activities 4. abnormal human activities and natural factors

What structure on the south african coast has a range of 63 km and releases flashes every 30 seconds?

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.