BIOCHEMISTS HAVE SOLVED (A) MANY OF THE MYSTERIES (B) ABOUT PHOTOS...

30. Biochemists have solved (A) many of the mysteries (B) about photosynthesis, the process which (C) plants make (D) food. V. Choose the one option that best completes the passage Yellowstone National Park, the first US national park, was (31) ... in 1872. It is one of the largest parks. It spreads about 3, 500 square miles or 9, 063 square kilometers (32) ... north-west Wyoming and parts of Idaho and Montana. It has many wild animals, (33) ... bears, buffalo, elk, deer, antelope, coyotes, and lynxes, and is famous for its tine scenery, hot springs and geysers (underground hot spring that shoot hot water or steam up into the air). There are about seventy geysers in the park. The famous is old Faithful. The park is a (34) ... tourist attraction. It has about three million (35) ... a year. It was made a World Heritage Site in 1978.