1. A new chemical was discovered and introduced
   into a culture containing one species of bacteria.
   Within a day, most of the bacteria were dead,
   but a few remained alive. Which statement best
   explains why some of the bacteria survived?
   (1) They had a genetic variation that gave them
   resistance to the chemical.
   (2) They were exposed to the chemical
   long enough to develop a resistance to it.
   (3) They mutated and became a different
   species after exposure to the chemical.
   (4) They absorbed the chemical and broke it
   down in their digestive systems.
   יכ
   2
   3