20. 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