Прочитайте текст. Заполните пропуски в предложениях под номерами В11-В16 соответствующими формами слов, напечатанных заглавными буквами справа от каждого предложения. TEST 16 (part 2)

B11

A recent study may have an answer to one of the greatest unsolved mysteries in science — what is the purpose of sleep? The work suggests it’s ...................... about making animals function more efficiently in their environments.

REAL

B12

...................... from the University of California, Los Angeles, conducted a study of the sleep times of a broad range of animals. They discovered much variation.

SCIENCE

B13

You may think it ...................... but some migrating birds canfly non-stop for up to 90 hours.

POSSIBLE

B14

Pythons and bats are among the longest ...................... at over 18 hours a day.

SLEEP

B15

Human babies need 16 hours and their health and intellectual ...................... depend on sleeping properly.

DEVELOP

B16

Most of us probably feel we need around eight hours sleep to function well. Some people have ...................... in getting enough sleep and this may lead to serious health problems.

DIFFICULT