Assertion: Natural selection always leads to the evolution of more complex organisms.
Reason: Complexity is an advantageous trait that is favored by natural selection.
Both assertion and reason are true, and the reason is the correct explanation of the assertion.
Both assertion and reason are true, but the reason is not the correct explanation of the assertion.
The assertion is true, but the reason is false.
Both assertion and reason are false.
Natural selection does not necessarily lead to the evolution of more complex organisms. Complexity can be advantageous in certain environments, but it is not always the case. In fact, there are many examples of simple organisms that are well-adapted to their environment and have been successful in evolving over long periods of time.
Option 4 is the correct answer.