Answer:
- Human life depends on air, water and food (in the primary level); and cloth and shelter (in the secondary level).
- Air is needed for respiration as well as circulation which are the important mechanism of the living organism.
- Besides, 70% of our body is made up of water and it forms an essential part in various functions of our body.
- A healthy and nutritious food is essential for our existence and survival.
- Food is required for growth, development and body repair.
- All these three primary elements protect the body from diseases and provide energy for doing all life functions.
- Cloth protects from heat, cold and rain. It also gives an attractive feature to body.
- Our home provides shelter to us and protects us from changing environments. Thus, human life depends on these factors for the survival.
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