Over time, a mutation develops that allows many of the San Diego urchins to resist the toxin, a genetic trait which they pass on to their offspring. Which of the following statements is true?
1) The San Diego urchins will become extinct due to the mutation.
2) The toxin will become more potent over time.
3) The San Diego urchins will become immune to all toxins.
4) The genetic trait for toxin resistance will spread through the San Diego urchin population.