Yes, ''to'' is a preposition. It is commonly used to indicate direction, location, or relationship between items in a sentence.
Complex
what peposition with word profit
Don't put the peposition at the end of a sentence. Good luck at Slippery Rock LOSER. YOU ARE NOT GOING TO SUCCEED IN LIFE. WHAT IS YOUR GPA? 1.5. LOOOOSSSSEEEERRRR!!!!!!!
The simple subject is "islands", the complete subject is "Some islands", and both "off" and "of" are prepositions.