the location on existing dna polymer where the 5' phosphate of an incoming nucleotide will form a phosphodiester bond

The main reason that you should secure loose objects in your car before you drive is that a. objects too close to the engine may be affected by the heat b. they are likely to get damaged moving around your car c. they may be thrown into a spot that disrupts your driving d. they will be more easily retrieved from a single storage location