Worksheet on the respiratory system showing labeled organs and fill-in-the-blank questions.

Let's solve the worksheet step by step and explain each answer.

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1.1. Answer the questions using the words provided in the box:

Words: oxygen, involuntary, carbon dioxide

#### a) What gas does human beings take in when we breathe?
We inhale _________.
✔ Answer: *oxygen*
Explanation: When we breathe in (inhale), we take in oxygen from the air. Oxygen is essential for cellular respiration, where it helps produce energy in our cells.

#### b) What gas does human beings eliminate during respiration?
We exhale _________ _________.
✔ Answer: *carbon dioxide*
Explanation: During cellular respiration, our cells produce carbon dioxide as a waste product. This gas is transported back to the lungs and exhaled out of the body.

#### c) Is respiration a voluntary or involuntary movement?
It is an _________ movement.
✔ Answer: *involuntary*
Explanation: Breathing (respiration) is controlled by the brainstem and happens automatically without conscious thought. While we can control breathing temporarily (e.g., holding our breath), it is primarily an involuntary process.

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1.2. Name the organs of the respiratory system

We are given a diagram with numbered labels and a list of organs:

Organs to choose from:
- Nose
- Bronchioles
- Larynx
- Trachea or windpipe
- Bronchi
- Pharynx
- Lungs
- Alveolar sacs or alveoli

Now, let’s identify each labeled part based on the diagram:

#### 1) → Nose
✔ The topmost structure shown is the nose, which is the entry point for air into the respiratory system.

#### 2) → Pharynx
✔ Below the nose, the air passes through the pharynx (throat), which connects the nasal cavity to the larynx.

#### 3) → Larynx
✔ The larynx (voice box) is located below the pharynx and above the trachea.

#### 4) → Trachea or windpipe
✔ The long tube leading down from the larynx is the trachea (windpipe). It carries air to the bronchi.

#### 5) → Bronchi
✔ The trachea splits into two main branches called bronchi (singular: bronchus), one going to each lung.

#### 6) → Bronchioles
✔ Inside the lungs, the bronchi divide into smaller tubes called bronchioles.

#### 7) → Alveolar sacs or alveoli
✔ At the end of the bronchioles are tiny air sacs called alveoli (or alveolar sacs), where gas exchange occurs (oxygen enters blood, carbon dioxide exits).

#### a) → Lungs
✔ The large pink structures on either side are the lungs, where the entire process of gas exchange takes place.

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✔ Final Answers:

#### 1.1.
a) We inhale oxygen.
b) We exhale carbon dioxide.
c) It is an involuntary movement.

#### 1.2. Diagram Labels:
1) Nose
2) Pharynx
3) Larynx
4) Trachea or windpipe
5) Bronchi
6) Bronchioles
7) Alveolar sacs or alveoli
a) Lungs

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This completes the worksheet! Let me know if you'd like a printable version or need help understanding any part further.