A scientist noted that, over a period of 10 years, a Florida beetle species gradually became resistant to an insecticide. Which statement best explains this in terms of natural selection?
a
The insecticide mutated the beetles exposed to the biggest doses.
b
Some beetles used the insecticide as a source of food.
c
Beetles learned to avoid the spray and passed this knowledge to their offspring.
d
Those beetles with natural resistance to the insecticide had the most offspring.
d
Those beetles with natural resistance to the insecticide had the most offspring.