**Explanation:**

The correct answer is option 'C' - Nutrition.

**Definition of Nutrition:**
Nutrition is the process by which organisms obtain and utilize nutrients for growth, maintenance, and repair of tissues. It involves the intake of food, digestion, absorption, assimilation, and elimination of waste products.

**Intake of Food in Animals:**
Animals take in food through their mouth, which is the opening of the digestive system. The process of intake of food in animals involves several steps:
1. Ingestion: The process of taking food into the mouth is called ingestion. Animals have different methods of ingestion depending on their feeding habits. For example, herbivores eat plants, carnivores eat other animals, and omnivores eat both plants and animals.
2. Chewing or Grinding: Some animals, like humans, have teeth that help in chewing or grinding the food into smaller pieces, increasing its surface area for better digestion.
3. Swallowing: After the food is chewed, it is swallowed and passes through the esophagus into the stomach.
4. Digestion: In the stomach and intestines, the food is broken down into simpler forms through the process of digestion. Digestive enzymes and acids help in the breakdown of complex substances into simpler ones.
5. Absorption: The digested food is then absorbed into the bloodstream through the walls of the small intestine.
6. Assimilation: Once absorbed, the nutrients are transported to various cells and tissues of the body, where they are utilized for growth, repair, and energy production.
7. Elimination: Waste products, such as undigested food and other indigestible materials, are eliminated from the body through the rectum and anus in the form of feces.

**Intake of Food in Plants:**
Plants, being autotrophs, synthesize their own food through the process of photosynthesis. They intake food in the following steps:
1. Absorption of Water and Minerals: Plants absorb water and minerals from the soil through their roots. The root hairs present on the surface of the roots increase the surface area for absorption.
2. Absorption of Carbon Dioxide: Plants absorb carbon dioxide from the atmosphere through tiny pores called stomata present on the leaves.
3. Photosynthesis: In the presence of sunlight, chlorophyll present in the leaves captures the energy and converts carbon dioxide and water into glucose (food) and oxygen. This process is called photosynthesis.
4. Translocation: The synthesized food (glucose) is transported to different parts of the plant through the vascular tissues (xylem and phloem).
5. Utilization: The glucose produced during photosynthesis is utilized by the plant for growth, development, and energy production.
6. Storage: Excess glucose is stored in the form of starch in various plant parts, such as roots, stems, and fruits.
7. Excretion: Plants do not have a separate excretory system like animals. They eliminate waste products, such as oxygen and water vapor, through stomata during the process of transpiration.

Therefore, the correct answer is option 'C' - Nutrition, as it encompasses the complete process of intake, digestion, absorption, assimilation, and elimination of food in both animals and plants.

The answer is c because if you see the definition of nutrition in the book you will get the same sense which is given in this question.