Islam and Muhammed -- I give a sensible arguement and expect sensible answers?

Why do Muslims say Islam is the 1 true religion when you see the following?1.around 70% of the Quran was copied from the Bible.2.Muhammed's only claim to being an authentic prophet was the beautiful writing style of the Quran.3.When Muhammed contradicted himself he said that Allah abrogated (cancelled) certain commands. 4. Since Allah's words and the Quran are eternal and have always existed-how is it that the "Satanic verses"got in?5. If the Quran is God's word,why does it say that "Egypt owes its beauty to the rain" when actually it is because of the Nile.6.Muslims state that Clic Arabic is a sacred language,so why did the Quran borrow much vocabulary from Ethiopian,Syriac+others?7.If the Quran is a miracle why do Muslims not believe that Beethoven (he was deaf from birth)also was a prophet of God,or Mozart whose 1st composition was at age 5 should be deemed a prophet too,as well as Shakespeare. also the Ahadith says Muhammed did miracles,the Quran says he did none--contradiction