13. For questions 1-27, read the texts below and decide which answer best fits each gap.A Cosmic DirectoryScientists at Puerto Rico University in Arecibo have recently (10) _________ a cosmic directory that lists the planets and moons most likely to (11)__________ alien life. They created the catalogue to make sense of the ever-increasing number of distant worlds that are visible with modern telescopes. They believe it will help astronomers, and others with an interest, to compare faraway worlds and keep (12)_________ on the most habitable ones as researchers discover them.The catalogue ranks the habitability of planets and moons according to three (13)________ : their surface temperature, their similarity to Earth and their capacity to (14)__________ organisms that (15) __________ at the bottom of the food chain. It suggests that among hundreds of candidates, only a few planets are (16)_________ habitable, and gives high (17)___________ for habitability to even fewer. The database also holds information on the (18)__________ of the planets, their probable mass and the type and age of the stars they orbit.