(>_<)英文解釈について（>_<）
下記英文解釈について教えていただきたいです。よろしくお願いします。
(1-33) Over the course of six moon landings a dozen astronauts brought back rock samples and photographic records that((1) 関代の所有格でしょうか?) increased man’s understanding of the solar system.
(1-34) The sun in the largest object in our solar system but is only one star among hundreds of billions in the Milky Way, which ((2)The sun の後にwhichと続けていいのでしょうか?)in turn is only one galaxy among billions that((3)関代主格で先行詞にonlyがあるからthatでしょうか?) extend for billions of light-years into space. Even farther away are tiny, brilliant points of light called quasars that ((4)thatを使う理由は何でしょうか?)scientists are only beginning to understand.
(1-35) The earth is the only one planet in the solar system that ((5)thatは関係代名詞でしょうか？)only planet humans have explored extensively. Yet even after roaming((6)前置詞+名詞で副詞になるのでしょうか？)the earth for two million years, human still do not know much about the planet. Firsthand knowledge is restricted to the thin layer of rock and water extending a few kilometers below the earth’s surface and up to the highest stratum of the earth’s atmosphere.
Where((7)whereが先頭にくるときはいつでしょうか？)humans have not been able to venture, probes have been sent. The knowledge thus gained can often be applied t other planets that are believed to have been created in a similar way to the earth, which was born from dust and gases left over from the creation and atmosphere provides clues to what ((8)なぜwhatがくるのでしょうか？)explores may expect when they venture deep into space.
(1-36) In the earliest days after the earth was formed, the atmosphere of the planet consisted mainly of water, hydrogen, methane, and ammonia, a combination that ((9)thatは何用法でしょうか?)a combination would be deadly to most modern forms of life.
In fact, these very gases reacted with each other-prompted by lightning, ultraviolet light, or some other form of energy- to create chemical compounds from which ((10) whichは目的語の関係代名詞でしょうか?)began life on earth began.
Scientists have conducted experiments to recreate this process. By first producing a combination of gases similar to that of the earth’s atmosphere billions of years ago and then directing ((11)分詞でしょうか？)bolts of energy, to create a chemical reaction which produces amino acids and other chemical compounds found in all known forms of life.
