1.
Directions: After reading the passage below, fill in the blanks to make the passage coherent and grammatically correct. For the blanks with a given word, fill in each blank with the proper form of the given word; for the other blanks, use one word that best fits each blank.
Climate and Evolution
Most of the more than 6，000 species of frogs in the world lay their eggs in water. But many tropical frogs lay their eggs out of water, protects the eggs from aquatic predators（水生食肉动物），and increases their risk of drying out.
Justin Touchon, post-doctoral fellow at the Smithsonian Tropical Research Institute, （discover）that climate change in Panama might be altering frogs' course of evolution. analyzing long-term rainfall data collected by the Panama Canal Authority, he found that rainfall patterns are changing just as climate-change models predict. Over the past four decades, rainfall (become) more occasional during the wet season. The number of rainy days decreased, and the number of gaps between storms increased.
The eggs of the treefrog are extremely sensitive to drying. They die within a day there is no rain. Heavy rains encourage breeding, so as storms become off and on, the chance of rain within a day of being laid decreases and so egg survival.
weather patterns have changed, the advantage of laying eggs out of water has decreased, not only for treefrogs but potentially for many species. "Treefrogs can switch between laying eggs in water or on leaves, so they may live through the changes we are seeing in rainfall better than other species have lost the ability to lay eggs in water, "said Touchon." Being flexible in the place they put their eggs gives them more options and allows them to make decisions in a given habitat will increase the survival of their eggs. "