Nutrition: The Process of Energy Transfer for Life

The question asks for the term describing the intake of energy sources from outside the body for life processes.

Nutrition is the biological process where an organism takes in food (which contains energy sources) from its external environment and utilizes it for growth, metabolism, and other life functions.

Analyzing the Options

Let's examine why "nutrition" is the correct term and why the others are not suitable:

• Nutrition: This directly matches the definition required – taking in energy sources from outside the body.
• Excretion: This is the process of removing waste products, not taking in energy.
• Respiration: This process releases energy from food molecules *within* the body; it does not involve the initial intake of energy sources from outside.
• Digestion: This is the breakdown of food into absorbable molecules, which is a part of nutrition but not the overall process of energy transfer from outside.

Therefore, the transfer of a source of energy from outside the body of an organism for life processes is specifically defined as nutrition.