Which of these energy rescources has the fewest negative effects on the planet?
a: solar energy
b: nuclear energy
c: hydroelectric energy
d: petroleum

[fw.02]sinkholes are often formed as a result of the actions of. a. heat on recharge b. pressure on aquifers c. acid in groundwater d. minerals in hot springs

Match the letters with the correct terms

What are the 28 countries in the eu?