To solve this question, we need to evaluate both the Assertion (A) and the Reason (R) and check whether they are true or false, and if true, determine if the Reason (R) correctly explains the Assertion (A).
Assertion (A): River valleys are sparsely populated areas of the world.
Analysis: This statement is false. In reality, river valleys are some of the most densely populated areas in the world. This is because river valleys provide fertile land, access to water, and are conducive to agriculture, which supports larger populations. For example, the Nile Delta in Egypt, the Ganges Plain in India, and the Yangtze River Basin in China host large populations.
Reason (R): Water is the most important factor for life.
Analysis: This statement is true. Water is indeed crucial for all known forms of life. It is essential for drinking, irrigation in agriculture, and various industries, making it a vital factor for sustaining life and human settlements.
Now, let's evaluate the options:
Therefore, the correct answer is: (A) is false, but (R) is true.