Significance of transpiration:
 (a) It creates transpiration pull to facilitate ascent of sap.
 (b) Ascent of sap is necessary to make water available for photosynthesis.
 (c) It helps a plant to get rid of excess water. 

Leaves play important role in excretion in plants. Most of the carbon dioxide exits through stomata in leaves. Many excretory products accumulate in leaves. Plants shed leaves to get rid excretory products.

Amoeba shows holozoic nutrition which is comprised of following steps:
 Ingestion, Digestion, Absorption, Assimilation and Egestion

 
Ingestion: Amoeba makes finger-like projections outside its body. These projections are called pseudopodia. Amoeba traps food particle with pseudopodia. After that, amoeba takes in the food particle; along with water.
Digestion: Amoeba makes food vacuole after ingesting the food particle. Enzymes are released in the food vacuole for digestion.
Absorption: After digestion, nutrients enter the cytoplasm through osmosis.
Assimilation: Nutrients are utilized by the cell for various purposes.
Egestion: Food vacuole goes near the cell membrane to empty its contents outside the cell. This results in expulsion of waste materials from the cell. 

The human alimentary canal has following parts:
Buccal Cavity: Buccal cavity contains tongue, teeth and salivary glands. Food enters the digestive system through buccal cavity.
Oesophagus: Buccal cavity is connected to a long tube-like structure; called oesophagus. Oesophagus has a valve to prevent the backflow of food into mouth.
Stomach: Stomach is a J-shaped organ. The buccal cavity opens into the stomach. Walls of stomach are composed of muscles. Gastric glands are present in the stomach. These glands secrete hydrochloric acid, pepsin and mucus.
Small Intestine: This is long and highly coiled structure. The lumen of the small intestine is smaller than that of large intestine. The stomach opens into small intestine. The hepatopancreatic duct opens into the small intestine. Villi are present in small intestine to facilitate absorption of food.

Large Intestine: This is shorter than small intestine. The lumen of large intestine is larger than that of small intestine.
Rectum: Large intestine opens into rectum. Waste materials and undigested food are stored in rectum. 
 

Breathing involves two step, viz. inhalation and exhalation.
Inhalation: The process of taking in air called inhalation. During this process, ribs come out and diaphragm moves down. This increases the volume inside the lungs and reduces the pressure in lungs. As a result, air moves towards the lungs.
Exhalation: The process of giving out air is called exhalation. During this process, ribs go in and diaphragm moves up. This reduces the volume inside the lungs and increases the pressure in lungs. As a result, air moves out of the lungs. 

Importance of soil for plant growth:
 (a) Soil provides the base on which a plant can grow.
 (b) Soil serves as reservoir of water for plants.
 (c) Soil serves as reservoir of different minerals which are essential for growth of plants.
 (d) Soil contains many organic materials which provide nutrients to plants. 

Digestion of carbohydrates: Digestion of carbohydrates begins from buccal cavity.
Salivary amylase converts starch into sugar. Other complex carbohydrates are converted into glucose in the small intestine.
Digestion of Proteins: Protein is partially digested in the stomach. For this, stomach secretes the enzyme pepsin. In small intestine, pancreatic juice provides the enzymes trypsin and chymotrypsin. These enzymes complete the digestion of proteins.
 Digestion of Fats: Digestion of fats takes place in small intestine. Bile; from liver; emulsifies the fat. Due to this, fat is broken into small globules. This makes it easier for the enzyme to digest fat. Lipase is the enzyme which converts fat into glycerol and fatty
acid. 

Photosynthesis is the process by which green plants prepare their food in the presence of sunlight. Green plants utilize carbon dioxide and water to make carbohydrate. The reaction of photosynthesis can be shown by following equation:

The whole process of Photosynthesis is composed of following steps:
 (a) Absorption of light energy by chlorophyll
 (b) Conversion of light energy into chemical energy
 (c) Splitting of water molecules into hydrogen and oxygen.
 (d) Reduction of carbon dioxide to form carbohydrate
 These steps need not take place one after another immediately. For example;
desert plants take up carbon dioxide at night to make an intermediate. During daytime,  they make carbohydrate. After photosynthesis, carbohydrate is converted into starch and starch is stored in different plant organs.