Function of Body Systems worksheet - Free Printable

Let's solve this step by step. The task is to match each function (numbered 1–10) with the correct body system (lettered A–J).

We’ll go through each function and identify which body system performs that function.

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Step-by-step Matching:

1. Breaks down food into smaller food nutrients.
→ This is the job of the Digestive System.
✔ Match: B. Digestive System

2. Protects internal organs and gives the body shape.
→ This is the role of the Skeletal System (bones provide structure and protection).
✔ Match: J. Skeletal System

3. Helps the body to move.
→ Muscles allow movement. This is the Muscular System.
✔ Match: F. Muscular System

4. Uses food (glucose) and oxygen to make energy.
→ This process is cellular respiration, which happens in cells, but it involves the Respiratory System (provides oxygen) and Digestive System (provides glucose). However, the main system responsible for gas exchange (oxygen in, CO₂ out) is the Respiratory System. But note: Energy production occurs at the cellular level using inputs from multiple systems. Still, the respiratory system is key in providing oxygen needed for energy.
But wait — actually, this function is not directly a system’s primary role, but since we’re matching to systems, and the respiratory system supplies oxygen, and the circulatory system delivers it, the best match here is I. Respiratory System? Let’s think again.

Actually, the process of using glucose and oxygen to make energy (ATP) happens in cells, but the Respiratory System provides the oxygen. However, the primary system involved in delivering oxygen and nutrients to cells is the Circulatory System.

Wait — let's reconsider:
- Respiratory System: takes in oxygen and releases CO₂.
- Circulatory System: transports oxygen and glucose to cells.

But "uses food and oxygen to make energy" happens in cells, so no single system does it alone. However, the Respiratory System is most directly involved in supplying oxygen. But the best answer is likely I. Respiratory System, because it brings in oxygen.

However, looking at the list, no option says "Cellular Energy Production", so we must pick the system most closely tied to supplying oxygen.

But option I is Respiratory System, and its function is to take in oxygen and release waste gases. So yes, it contributes.

But wait: the muscle cells use glucose and oxygen — but that's not the system itself.

Actually, the function "uses food and oxygen to make energy" is a cellular process, but the system that enables this is the Respiratory System (for O₂) and Digestive System (for glucose), and Circulatory System (to deliver both).

But among the options, none is "Cellular Respiration", so perhaps the question means which system helps in this process?

Looking back:
- The Respiratory System brings in oxygen → essential for energy production.
- The Circulatory System delivers oxygen and glucose to cells.

But "uses food and oxygen to make energy" is not a system’s function per se — it's what cells do.

However, if we interpret it as "the system that provides oxygen", then it's Respiratory System.

But let’s look at the diagram:
- Respiratory System: "takes in oxygen and releases waste gases" → matches part of this.

So, I. Respiratory System is the best fit.

✔ Match: I. Respiratory System

Wait — but energy production also requires glucose, which comes from digestion. But the key point is that oxygen is required, and only the Respiratory System brings in oxygen.

So yes, I. Respiratory System.

5. Removes waste materials (e.g., urine) from the body.
→ This is the Excretory System (kidneys, bladder, ureters).
✔ Match: C. Excretory System

6. Transports oxygen, food nutrients, etc. around the body.
→ This is the Circulatory System (blood vessels, heart, blood).
✔ Match: A. Circulatory System

7. Produces hormones that are released directly into the bloodstream.
→ This is the Endocrine System (glands like pituitary, thyroid, adrenal).
✔ Match: D. Endocrine System

8. Helps the body fight infection and kill germs and bacteria.
→ This is the Lymphatic System (part of immune defense: lymph nodes, white blood cells).
✔ Match: E. Lymphatic System

9. Transports electrical messages (impulses) around the body.
→ This is the Nervous System (brain, spinal cord, nerves).
✔ Match: G. Nervous System

10. Allows the body to make young ones (offspring).
→ This is the Reproductive System.
✔ Match: H. Reproductive System

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Now let’s double-check the diagram below:

- Skeletal System: provides structure and protects organs → matches #2
- Muscular System: supports and allows movement → matches #3
- Digestive System: breaks down food and absorbs nutrients → matches #1
- Respiratory System: takes in oxygen, releases waste gases → matches #4 (uses oxygen)
- Nervous System: controls sensation, thought, movement → matches #9
- Circulatory System: transports oxygen, nutrients, carries away wastes → matches #6

So far, all match.

But wait — #4: Uses food and oxygen to make energy — is this really the Respiratory System?

Let’s reconsider:
- Respiratory System: brings in oxygen.
- Circulatory System: delivers oxygen and glucose to cells.
- Cells: use them to make energy.

But no system directly "uses" food and oxygen to make energy — that’s cellular.

However, the Respiratory System is the one that supplies oxygen, which is critical.

But the diagram says:
> Respiratory system: takes in oxygen and releases waste gases

And #4 says: "Uses food (glucose) and oxygen to make energy"

This implies using both, so both digestive and respiratory contribute.

But the system that primarily handles oxygen intake is the Respiratory System.

Alternatively, could it be Circulatory System? Because it transports both oxygen and glucose?

But #6 already says: "Transports oxygen, food nutrients..." → that’s Circulatory System

So #4 cannot be A (Circulatory) — because that’s already used for transport.

Wait — maybe #4 is not the Respiratory System?

Let’s re-evaluate:

Is there a system that uses food and oxygen to make energy?

No — that’s cellular metabolism.

But the only system listed that deals with oxygen and energy is Respiratory or Circulatory.

But #6 is clearly Circulatory System → transports oxygen and nutrients.

So #4 must be Respiratory System, even though it doesn’t *use* the food — it provides oxygen.

But the function says "uses food and oxygen", so maybe it's misleading.

Wait — perhaps the intended answer is I. Respiratory System, because it provides oxygen, and food is from digestion.

But digestion provides glucose, respiration provides O₂, circulation delivers both.

But no system is labeled "Metabolic System", so we have to pick the best.

Looking at the diagram, Respiratory System is described as taking in oxygen and releasing waste gases — which is part of energy production.

So #4 → I. Respiratory System

But let’s check if any other system fits better.

What about Muscular System? Muscles use glucose and oxygen to contract — but that’s a result, not the system’s main function.

The main function of the muscular system is movement.

So no.

Therefore, I. Respiratory System is still best.

But wait — #4 says: "Uses food (glucose) and oxygen to make energy"

This is cellular respiration, which requires:
- Glucose (from digestive system)
- Oxygen (from respiratory system)
- Transport (circulatory system)

But no single system performs the whole process.

However, the respiratory system provides the oxygen, which is essential.

So I. Respiratory System is the best match.

Alternatively, some might argue Circulatory System, but #6 already covers transport.

So #4 = I. Respiratory System

Yes.

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Final Answers:

1. B – Digestive System
2. J – Skeletal System
3. F – Muscular System
4. I – Respiratory System
5. C – Excretory System
6. A – Circulatory System
7. D – Endocrine System
8. E – Lymphatic System
9. G – Nervous System
10. H – Reproductive System

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✔ Completed Worksheet:

```
______ 1. Breaks down food into smaller food nutrients. B. Digestive System
______ 2. Protects internal organs and gives the body shape. J. Skeletal System
______ 3. Helps the body to move. F. Muscular System
______ 4. Uses food (glucose) and oxygen to make energy. I. Respiratory System
______ 5. Removes waste materials (e.g., urine) from the body. C. Excretory System
______ 6. Transports oxygen, food nutrients, etc. around the body. A. Circulatory System
______ 7. Produces hormones that are released directly into the bloodstream. D. Endocrine System
______ 8. Helps the body fight infection and kill germs and bacteria. E. Lymphatic System
______ 9. Transports electrical messages (impulses) around the body. G. Nervous System
______ 10. Allows the body to make young ones (offspring). H. Reproductive System
```

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Explanation Summary:

- Digestive System breaks down food → #1
- Skeletal System provides structure and protection → #2
- Muscular System enables movement → #3
- Respiratory System supplies oxygen for energy production → #4
- Excretory System removes waste like urine → #5
- Circulatory System transports substances → #6
- Endocrine System produces hormones → #7
- Lymphatic System fights infection → #8
- Nervous System sends electrical signals → #9
- Reproductive System enables reproduction → #10

✔ All matched correctly based on biological functions and the provided diagrams.