The correct answer to the question is option 1 – Metabolism. Energy is required for the maintenance of life processes in organisms. Metabolism is the process by which organisms convert food into energy that can be used for various activities.

Now let`s dissect each option to better understand why the correct answer is metabolism:

Option 2, Phagocytosis, refers to the process by which cells engulf and digest solid particles such as bacteria. While this process requires energy, it is not the primary process involved in obtaining energy for maintenance of life.

Option 3, Photorespiration, is a process that occurs in plants during photosynthesis where oxygen is used instead of carbon dioxide. While it is a part of energy metabolism in plants, it does not directly answer the question or encompass all organisms.

Option 4, Decomposition, refers to the breakdown of organic matter into simpler substances. While decomposition releases energy in the form of heat, it is not the specific process by which energy is obtained for maintenance of life.

In conclusion, while the options provided may involve energy processes, only option 1, Metabolism, specifically refers to the process by which energy is obtained for maintenance of life.