Explanation:

- Statement 1: Population change can indicate economic development. As regions grow economically, they often attract people due to better job opportunities and living standards. Conversely, high migration out might suggest economic decline.

- Statement 2: Population change can reflect social upliftment. Improved education, healthcare, and social services can lead to population growth as people seek better living conditions. So, it can be an indicator of social upliftment.

- Option 1: "1 only": This is partially correct. While it's true for economic development, statement 2 is also important.

- Option 2: "2 only": This is incorrect. Statement 2 is not entirely wrong, but it doesn't cover statement 1.

- Option 3: "Both 1 and 2": This is the most comprehensive choice.

- Option 4: "Neither 1 nor 2": Incorrect because both statements have relevance.