What does 50 percent humidity mean?

Based on this map, which statement about africa’s economic activity is most accurate? a) coastal countries are all members of opec b) economic development is more common with opec nations c) coastal countries have more access to productive resources d) economic development is more common above the sahara desert

According to the earth science reference tables, during which geologic time period were the continents of north america,south america, and africa closest together?

5. what is a red giant? can our sun become a red giant? why or why not?