In the early 1900s, California citrus growers sprayed their trees with cyanide gas to kill scale insects. By 1914, some scale insects were surviving the spraying
and eventually the whole population showed resistance to cyanide. Which of the following statements best explains how resistance to cyanide spread in the
scale insect population?
a Parasites infecting the insect population carried the trait from insects with a resistance gone to insects without a resistance gene
Predators put greater selection pressure on insects with a resistance gene than on insects without a resistance gene.
Insects with a resistance gene survived the first cyanide sprayings and passed the gene to their offspring.
Insects without a resistance gene underwent mutation upon contact with the cyanide to acquire resistance