Worksheet for labeling the parts of the human ear and dividing it into three sections.

Let's solve the problem step by step based on the worksheet titled "The Human Ear".

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1a. Label the parts of the ear using the words from the box:

Words to use:
- cochlea
- eardrum
- semicircular canal
- ear canal
- pinna
- auditory nerve
- ossicles
- Eustachian tube
- oval window

We need to match each label to the correct part of the ear diagram.

#### Step-by-step identification:

1. Pinna – This is the visible outer part of the ear, the flappy part that collects sound waves.
- → The topmost external structure on the left side of the diagram.

2. Ear canal – The tube that leads from the pinna into the middle ear.
- → The tunnel-like passage leading inward from the pinna.

3. Eardrum (tympanic membrane) – A thin membrane that vibrates when sound waves hit it.
- → Located at the end of the ear canal; shown as a thin barrier separating outer and middle ear.

4. Ossicles – Three small bones in the middle ear: malleus, incus, stapes. They transmit vibrations.
- → The three tiny bones connected in a chain just behind the eardrum.

5. Oval window – A membrane-covered opening between the middle ear and inner ear where the stapes bone connects.
- → The small circular opening where the last ossicle (stapes) attaches to the inner ear.

6. Cochlea – The spiral-shaped organ in the inner ear responsible for hearing.
- → The spiral-shaped structure on the right side of the diagram.

7. Semicircular canals – Three fluid-filled loops that help with balance.
- → The three looped structures above the cochlea.

8. Auditory nerve – Carries electrical signals from the cochlea to the brain.
- → The nerve extending out from the cochlea toward the brain (shown as a line going upward).

9. Eustachian tube – Connects the middle ear to the throat, equalizing pressure.
- → The tube running downward from the middle ear (behind the eardrum), connecting to the throat area.

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✔ Now, let’s assign the labels to the blank boxes:

From left to right, following the arrows:

1. Pinna (outer flap)
2. Ear canal (inside the pinna)
3. Eardrum (after ear canal)
4. Ossicles (middle ear bones)
5. Oval window (where ossicles connect to inner ear)
6. Cochlea (spiral shape)
7. Semicircular canals (loops above cochlea)
8. Auditory nerve (coming from cochlea)
9. Eustachian tube (tube from middle ear)

> Note: The exact order depends on how the lines are drawn. Based on typical diagrams:
>
> - Leftmost two boxes: Pinna and Ear canal
> - Middle section: Eardrum, Ossicles, Oval window
> - Right side: Cochlea, Semicircular canals, Auditory nerve, Eustachian tube

But since the image shows 9 labels and 9 blanks, here’s the likely matching:

| Blank | Part |
|-------|------|
| 1 | Pinna |
| 2 | Ear canal |
| 3 | Eardrum |
| 4 | Ossicles |
| 5 | Oval window |
| 6 | Cochlea |
| 7 | Semicircular canal |
| 8 | Auditory nerve |
| 9 | Eustachian tube |

> ⚠️ Double-check the arrow directions on your diagram — but this is the standard labeling.

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1b. Draw two vertical lines to divide the ear into three sections. [4 marks]

The human ear is divided into:

1. Outer ear
2. Middle ear
3. Inner ear

#### How to divide:

- First vertical line: Draw it just after the ear canal, before the eardrum. This separates the outer ear (pinna + ear canal) from the middle ear.
- Second vertical line: Draw it after the ossicles, before the cochlea. This separates the middle ear from the inner ear.

#### Labels:
- Left section: Outer ear
- Middle section: Middle ear
- Right section: Inner ear

> ✔ So, draw two vertical lines:
> 1. One at the eardrum (separating outer and middle)
> 2. One at the oval window / start of cochlea (separating middle and inner)

Then label:
- Outer ear
- Middle ear
- Inner ear

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✔ Final Answer Summary:

#### 1a. Labels (from left to right, top to bottom):
1. Pinna
2. Ear canal
3. Eardrum
4. Ossicles
5. Oval window
6. Cochlea
7. Semicircular canal
8. Auditory nerve
9. Eustachian tube

> *(Note: The exact positions depend on arrow placement — adjust if needed.)*

#### 1b. Diagram division:
- Draw two vertical lines:
- First: at the eardrum
- Second: at the start of the cochlea
- Label the sections:
- Outer ear (left)
- Middle ear (middle)
- Inner ear (right)

This shows the three main divisions of the ear.

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Let me know if you'd like a visual sketch or further explanation!