Educational worksheet on the human respiratory system, featuring a labeled diagram and a table on gas exchange.

Let's solve this step by step. The image is a worksheet about the human respiratory system, with two main parts:

1. Labeling the diagram of the human respiratory system.
2. Answering questions based on gas exchange and completing sentences.

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🔹 Part 1: Label the Diagram

We are given a list of terms to label the parts of the respiratory system:

- alveoli
- bronchi
- bronchiole
- diaphragm
- epiglottis
- larynx
- lung
- mouth
- nasal passage
- nostrils
- pharynx
- pleura
- trachea

Now, let’s identify each part in the diagram (based on standard anatomy):

From top to bottom:

1. Nostrils – openings of the nose
2. Nasal passage – inside the nose
3. Mouth – alternative entry point
4. Pharynx – throat, common passage for air and food
5. Epiglottis – flap that covers the larynx during swallowing
6. Larynx – voice box
7. Trachea – windpipe
8. Bronchi – two main branches from trachea into lungs
9. Bronchiole – smaller branches within lungs
10. Alveoli – tiny air sacs where gas exchange occurs
11. Lung – organ containing bronchi, bronchioles, alveoli
12. Diaphragm – dome-shaped muscle below lungs
13. Pleura – thin membrane covering the lungs

> Note: The pleura is often labeled around the outside of the lung.

So, labeling from top to bottom (as per lines):

1. Nostrils
2. Nasal passage
3. Mouth
4. Pharynx
5. Epiglottis
6. Larynx
7. Trachea
8. Bronchi
9. Bronchiole
10. Alveoli
11. Lung
12. Diaphragm
13. Pleura

*(Note: The exact line positions may vary slightly depending on how the diagram is drawn, but this is the standard anatomical order.)*

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🔹 Part 2: Gas Exchange Questions

#### Table:
| Gas | Inhaled (%) | Exhaled (%) |
|----------------|-------------|-------------|
| Oxygen (O₂) | 20.71% | 14.6% |
| Carbon dioxide (CO₂) | 0.04% | 4.0% |
| Water (H₂O) | 1.25% | 5.9% |

#### Q1. What gas is removed from inhaled air?

Answer: Oxygen (O₂)
→ Because its percentage decreases from 20.71% to 14.6%, meaning it's absorbed by the body.

#### Q2. What gases are added to inhaled air and then exhaled?

Answer: Carbon dioxide (CO₂) and water (H₂O)
→ CO₂ increases from 0.04% to 4.0% (waste product of respiration).
→ Water vapor increases from 1.25% to 5.9% (moisturized air).

#### Q3. Which gas shows the greatest difference in percent between inhaled and exhaled air?

Let’s calculate differences:

- O₂: 20.71% - 14.6% = 6.11%
- CO₂: 4.0% - 0.04% = 3.96%
- H₂O: 5.9% - 1.25% = 4.65%

➡️ Oxygen (O₂) has the largest percentage change.

✔ Answer: Oxygen (O₂)

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🔹 Part 3: Complete the Sentence

> Inspired air, rich in oxygen, enters the body through the nostrils or mouth. It passes through the pharynx and larynx, or voice box, and into the trachea. Air then enters each lung, which branches into bronchi, and finally into the air sacs or alveoli of the lungs. The lungs are housed in the thoracic cavity that is bound on the bottom by a thin layer of muscle, the diaphragm. Each lung is covered by a very thin pleura membrane. In the alveoli, carbon dioxide is exchanged for oxygen.

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✔ Final Answers Summary:

#### Labeling (from top to bottom):
1. Nostrils
2. Nasal passage
3. Mouth
4. Pharynx
5. Epiglottis
6. Larynx
7. Trachea
8. Bronchi
9. Bronchiole
10. Alveoli
11. Lung
12. Diaphragm
13. Pleura

#### Gas Exchange Questions:
1. Oxygen (O₂)
2. Carbon dioxide (CO₂) and water (H₂O)
3. Oxygen (O₂)

#### Fill-in-the-blank sentence:
> Inspired air, rich in oxygen, enters the body through the nostrils or mouth. It passes through the pharynx and larynx, or voice box, and into the trachea. Air then enters each lung, which branches into bronchi, and finally into the air sacs or alveoli of the lungs. The lungs are housed in the thoracic cavity that is bound on the bottom by a thin layer of muscle, the diaphragm. Each lung is covered by a very thin pleura membrane. In the alveoli, carbon dioxide is exchanged for oxygen.

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