Read the following passage and mark the letter A, B, C or D on your answer sheet to indicate the correct word or phrase that best fits each of the numbered blanks:
Trees are among the biggest and longest-living things on Earth, some dating back longer than the oldest buildings. But (1) ______ being nice to look at, trees also play an important role in improving the quality of our lives. 

On a world-wide (2) ______ _____, forests help to slow down the effects of global warming by using up the gas known as carbon dioxide and giving (3) ______ the oxygen we need to breathe. 

At local neighborhood level, trees also (4) ______ important environmental benefits. They offer shade and shelter, which (5) ______ reduces the amount of energy needed to heat and cool nearby buildings; at the same time, they also remove other impurities from the air we breathe.

But (1) ______ being nice to look at, trees also play an important role in improving the quality of our lives.