What is referred to by 'a doppelganger'?

Based on the clue 'a doodad or a small piece of jewelry', what is the answer? Based on the clue 'a doom buggy transports you through this attractio...', what is the answer? What is associated with: a doomed boy in this 1954 novel declares i got the conch you let me speak? Based on the clue 'a doorsill or a point that must be exceeded to beg...', what is the answer? Based on the clue 'a dorgi was the royal result when one of qeiis cor...', what is the answer? Based on the clue 'a dot indicating a unit of numerical value on dice...', what is the answer? Based on the clue 'a dot on a die', what is the answer? Based on the clue 'a double bend in a road or a record label with tom...', what is the answer?