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. 

     Coincident with concerns about the accelerating loss of species and habitats has been a growing appreciation of the importance of biological diversity, the (18) ______ of species in a particular ecosystem, to the health of the Earth and human well-being. Much has been written about the diversity of terrestrial organisms, particularly the exceptionally rich life associated tropical rainforest habitats. Relatively little has been said, (19) ______, about the diversity of life in the sea even though coral reef systems are comparable to rain forest in terms of richness of life. 

     An alien exploring Earth would probably (20) ______ priority to the planet's dominants – most distinctive feature - the ocean. Humans have a bias toward land (21) ______ sometimes gets in the way of truly examining global issues. Seen from far away, it is easy to realize that landmasses occupy only one-third of the Earth's surface. Given that two thirds of the Earth's surface is water and that marine life lives at all levels of the ocean, the total three-dimensional living space of the ocean is perhaps 100 times (22) ______ than that of land and contains more than 90 percent of all life on Earth even though the ocean has fewer distinct species.

Read the following passage and mark the letter A, B, C, or D on your answer sheet to indicate the correct answer to each of the questions from 44 to 48.

Sylvia Earle is an underwater explorer and marine biologist, who was born in the USA in 1935. She became interested in the world's oceans from an early age. As a child, she liked to stand on the beach for hours and look at the sea, wondering that it must be like under the surface. When she was 16, she finally got a chance to make her first dive. It was this dive that inspired her to become an underwater explorer. Since then, she has spent more than 6,500 hours under water, and has led more than seventy expeditions worldwide. She has also made the deepest dive ever, reaching a record-breaking depth of 381 meters.

In 1970, she became famous around the world when she became the captain of the first all-female team to live under water. The team spent two weeks in an underwater "house". The research they carried out showed the damage that pollution was causing to marine life, and specially to coral reefs. Since then she has written several books and magazine articles in which she suggests ways of reducing the damage that is being done to the world's oceans. One way, she believes, is to rely on fish farms for seafood, and reduce the amount of fishing that is done the out at sea.

(Adapted from Complete IELTS by Rawdon Wyatt)

By then, the elite performers had all totaled 10000 hours of practice over the (43) ________of their lives, the merely good students 8000 hours and the future music teachers just over 4000 hours.