True. A protein becomes functional only when it reaches its tertiary shape (3D). It is not necessary for the protein to reach the quaternary stage, but that is just a more complex functioning protein. It really is just two tertiary merged together. Example is red blood cells.
DNA is unzipped by helicase at the origin of replication. There are several origins of replications in eukaryotic DNA replication, while only one in prokaryotic replication.
The answer could be any of the following:
* energy
* sugar
* carbohydrates
* (possibly even) food.
In the case of fish if you polute plastic into the ocean the water will break up the plastic and the fish will confuse the little particles of plastic as food and will try to eat it and can die
