Food, water, a place to live
Answer:
Atmosphere refers to the thin blanket of air that surrounds the earth.
It serves many important functions such as:
- It contains a mixture of gases that are essential for the existence of life on earth. For example, carbon dioxide is essential for photosynthesis and oxygen is essential for cellular respiration.
- It also serves as the reservoir of water in the form of water vapor. Thus, it forms an important constituent for the water cycle.
- It maintains the temperature of the earth. Through the greenhouse effect, it maintains the temperature of the earth in limited ranges.
- It protects the earth from harmful rays of the sun. For example, ozone inhibits the entry of most of the UV rays of the sun into the earth environment.
Answer:
Gas exchange is the delivery of oxygen from the lungs to the bloodstream, and the elimination of carbon dioxide from the bloodstream to the lungs. It occurs in the lungs between the alveoli and a network of tiny blood vessels called capillaries, which are located in the walls of the alveoli.
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Explanation: