Look up Dawrin's theory of evolution. Basically, fossil records show how life forms change over time through evolution.
Answer:
A closed circuit doesn't allow the flow of electrons. an open circuit does. example: if you turn off a switch in your house. you 'broke the circuit it is closed.
The survival of the 2 percent of the population is due to the presence of a gene obtained from other species. This gene must be responsible for developing resistance in the insects, against the insecticide that was used by the farmer. The gene got incorporated in only 2% of the insects and therefore, they survived and rest of them were susceptible to the insecticide and thus, died.
