Answer:
1: The three religions of Judaism, Christianity and Islam readily fit the definition of monotheism, which is to worship one god while denying the existence of other gods. But, the relationship of the three religions is closer than that: They claim to worship the same god.
2: Christianity believes in the Trinity where there are 3 parts to God, where Islam and Judaism believe that there is only one god. Judaism puts more emphasis on laws and following them completely than Christianity which is talks more of love and acceptance.
Explanation:
if thats too many words and come off as cheater vibes you can narrow it down to the important stuff, and mess with the words a little.