ATP is the energy currency in life. It’s the high energy molecule that stores the energy we need. Organisms get ATP by consuming food.
Length of time candle burns is the correct answer.
The replication fork is a structure that forms within the nucleus during DNA replication. It is created by helicases, which break the hydrogen bonds holding the two DNA strands together. The resulting structure has two branching "prongs", each one made up of a single strand of DNA.