Explain the example of insect resistance to pesticides as an instance of natural selection.

Define and explain the following terms: Variation and Survival of the Fittest.

Given below are two statements.
Statement-$I$: Elimination of particular alleles from a population due to natural disasters is called genetic drift.
Statement-$II$: Sudden temporary heritable change in the gene is called point mutation.
In the light of above statements,choose the most appropriate answer from the options given below:

Which of the following is an effective force in biological evolution?

Which organisms are considered the most adapted in the environment?

Which factors contribute to the success of organisms with variations?