Question

definition nutrition, respiration, transportation and excretion ​

Answer 1

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1.Nutrition is the science that interprets the nutrients and other substances in food in relation to maintenance, growth, reproduction, health and disease of an organism. It includes food intake, absorption, assimilation, biosynthesis, catabolism and excretion.

2.respiration is the movement of oxygen from the outside environment to the cells within tissues, and the transport of carbon dioxide in the opposite direction.

3. The transport of water, food, minerals, hormones and other substances from one part to another part inside the body of an organism is known as transportation.

4.Excretion is a process by which metabolic waste is eliminated from an organism. In vertebrates this is primarily carried out by the lungs, kidneys and skin. This is in contrast with secretion, where the substance may have specific tasks after leaving the cell. Excretion is an essential process in all forms of life. For example, in mammals urine is expelled through the urethra, which is part of the excretory system. In unicellular organisms, waste products are discharged directly through the surface of the cell.

Explanation:

Answer 2

Nutrition :

• It is a process by which an organism obtains nutrients from food and utilizes them to obtain energy ,building and repairing of get tissues.

• Nutrients are defined as the substances required for proper growth and maintenance of a body ie. these are materials which provide energy to an organism .

Respiration :

• Respiration is the process by which food taken through nutrition gets oxidized and release energy for performing various activities.

• It is defined as the process of biochemical oxidation of nutrients at cellular level.

• It occurs in the presence of specific enzymes at optimum temperature in the cells to release energy for various metabolic activities.

Transportation :

• During metabolism, cell produces some useful and some wasteful products.

• The substances that are useful need to be transported to other cells while harmful substances are to be eliminated.

• Circulatory system is formed in higher animals which transports this both type of materials to and fro to get their target parts within the body.

• The transport system of human beings consists of circulating fluid called blood, heart and blood vessels the circulatory system transports substances such as nutrients ,salts ,oxygen ,hormones, waste products etc. around the body.

Excretion :

• Excretion is the biological process by which an organisms removes harmful metabolic waste from the body.

• The mode of excretion is completely different in unicellular and multicellular organisms.