Match the following: Column A Column B 1. Noble gases a. Less than 1 % 2. Oxygen b. Gills 3. Nitrogen c. Spiracles 4. Fish d. 21 % 5. Insects e. 78 %

(1-a) The noble gases present in the atmosphere are less than 1%. Noble gases are helium, neon, argon, krypton, xenon, radon and oganesson. (2-d) Oxygen is one of the most important gas in the atmosphere because it allows us to breathe. The oxygen is essential components, the percentage of oxygen in the air is 21%. Plants generate oxygen during photosynthesis. (3-e) Nitrogen is the major component of air, it contains in the total ratio and does not support combustion. Plants and animals cannot use nitrogen directly from the atmosphere. (4-b) Most fish breathe underwater using the oxygen that is dissolved in water. But to absorb oxygen from water, fish use special organs called gills. Gills are full of blood vessels. (5-c) Insects are a small animal with six legs, two pairs of wings and a body which is divided into three parts. Insects breathe through openings in the thorax and abdomen called spiracles. Column A Column B 1. Noble gases a. Less than 1 % 2. Oxygen d. 21 % 3. Nitrogen e. 78 % 4. Fish b. Gills 5. Insects c. Spiracles