Educational worksheet illustrating the respiratory system with labeled diagrams and definitions for students to complete.

Let's solve each part of the question by identifying the correct organs of the respiratory system based on the diagram and definitions provided.

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3.1. Air enters the ________ and gets warm and moist.

✔ Answer: nasal cavity
- Air enters through the nasal cavity, where it is warmed, moistened, and filtered before moving further into the respiratory system.

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3.2. The ________ takes the air from the nasal cavity to the next organ and food to the oesophagus.

✔ Answer: pharynx
- The pharynx (throat) is a shared passage for both air (from the nasal cavity) and food (from the mouth), leading to either the larynx (for air) or the esophagus (for food).

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3.3. The air passes through the ________ where the vocal cords are.

✔ Answer: larynx
- The larynx (voice box) contains the vocal cords and is located below the pharynx. It helps in sound production and protects the trachea during swallowing.

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3.4. The ________ or ________ is a big tube.

✔ Answer: trachea / windpipe
- The trachea, also known as the windpipe, is a large tube that carries air from the larynx to the bronchi. It is supported by C-shaped cartilage rings to keep it open.

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3.5. The ________ are two tubes in the lungs.

✔ Answer: bronchi
- The bronchi (singular: bronchus) are the two main tubes that branch off from the trachea and enter each lung.

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3.6. The respiratory tract divides into two smaller tubes called ________.

✔ Answer: bronchioles
- After the bronchi, the airways divide into smaller branches called bronchioles, which lead to the alveoli.

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3.7. The ________, also called alveoli sacs, are millions of very small sacs. The gas exchange happens there.

✔ Answer: alveoli
- The alveoli are tiny air sacs in the lungs where gas exchange occurs — oxygen enters the blood and carbon dioxide exits.

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✔ Final Answers:

| Question | Answer |
|--------|--------|
| 3.1 | nasal cavity |
| 3.2 | pharynx |
| 3.3 | larynx |
| 3.4 | trachea or windpipe |
| 3.5 | bronchi |
| 3.6 | bronchioles |
| 3.7 | alveoli |

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🧠 Summary of the Pathway:

Air enters → Nasal cavity → Pharynx → Larynx → Trachea → Bronchi → Bronchioles → Alveoli (gas exchange)

This completes the respiratory system pathway and matches all labels correctly!