How does modern genetic modification of foods differ from selective breeding?

Animal bodies (and even plant bodies for that matter) are complex enough that life couldn't exist without enzymes. enzymes are usually large, complex biological catalysts that are expensive to make. enzymes speed up the rate of chemical reactions without being used up during the reaction (they can be reused many times). they are highly specific in the reactions they regulate. knowing what enzymes are and how they function, why does this explain why complex life forms could not exist if there were no enzymes.

What will happen if two of the base pairs of the stand of the dna are switched

The scales shown in the introduction measure mass, or the amount of matter in a particular object. the scientific law of conservation of mass states that matter cannot be created or destroyed during a chemical reaction, but it can change from one form to another. did the simulation support this scientific law? explain why or why not.