ScienceAges 13-15

Human body systems & organs

Connect major human organs and systems to digestion, circulation, respiration and coordination. Review suitability for your learners before teaching.

New variation Try interactive challenge Browse templates

Age band:Ages 10-12 Ages 13-15

Choose “Save as PDF” to keep a copy. Use your browser’s paper setting for A4 or Letter.

Worksheet StudioPractice pack · Ages 13-15

Human body systems & organs

Take your time. Show your thinking.

1. Where does digestion begin in the human body through chewing and the action of salivary amylase: in the mouth or in the large intestine?
Heart · Lungs · Digestive Tract
2. Which nutrient group is primarily needed for building and repairing body cells and muscle tissue (found in fish, eggs, beans and lentils): proteins or water?
Heart · Lungs · Digestive Tract
3. Which class of digestive enzymes breaks down proteins into amino acids: proteases or amylases?
Heart · Lungs · Digestive Tract
4. What are the tiny air sacs in the lungs where oxygen diffuses into the blood and carbon dioxide diffuses out: alveoli or villi?
Heart · Lungs · Digestive Tract
5. Which mineral is essential for building strong bones and teeth (found in dairy products, leafy greens and small fish): calcium or sodium?
Heart · Lungs · Digestive Tract
6. Which dome-shaped muscle beneath the lungs contracts and flattens when you inhale, increasing chest volume and drawing air in: the diaphragm or the bicep?
Heart · Lungs · Digestive Tract
7. Which microscopic blood vessels have walls only one cell thick to allow rapid exchange of oxygen, nutrients and waste with body tissues: capillaries or arteries?
Heart · Lungs · Digestive Tract
8. Why does the human stomach produce hydrochloric acid: to kill harmful bacteria and provide the acidic pH for pepsin (protease) enzymes, or to digest bones into gold?
Heart · Lungs · Digestive Tract
9. Which blood vessels carry blood BACK toward the heart and contain valves to prevent backflow: veins or arteries?
Heart · Lungs · Digestive Tract
10. Which muscular tube carries swallowed food from the mouth down to the stomach by wave-like contractions (peristalsis): the oesophagus (gullet) or the trachea (windpipe)?
Heart · Lungs · Digestive Tract
11. Which organ produces bile (stored in the gallbladder) to neutralise stomach acid and emulsify fats into tiny droplets: the liver or the lungs?
Heart · Lungs · Digestive Tract
12. In the human circulatory system, which blood vessels carry blood AWAY from the heart under high pressure with thick muscular walls: arteries or veins?
Heart · Lungs · Digestive Tract

12 questions · Seed 46 · Age guidance, not curriculum certification

View the answer key

Worksheet StudioAnswer key · Ages 13-15

Human body systems & organs

Answers and reasoning. Review before teaching.

1. Where does digestion begin in the human body through chewing and the action of salivary amylase: in the mouth or in the large intestine?
In the mouth
Teeth mechanically break down food while saliva begins digesting starch into maltose.
2. Which nutrient group is primarily needed for building and repairing body cells and muscle tissue (found in fish, eggs, beans and lentils): proteins or water?
Proteins
Proteins supply amino acids for growth and tissue repair.
3. Which class of digestive enzymes breaks down proteins into amino acids: proteases or amylases?
Proteases
Proteases (such as pepsin and trypsin) hydrolyse proteins into amino acids.
4. What are the tiny air sacs in the lungs where oxygen diffuses into the blood and carbon dioxide diffuses out: alveoli or villi?
Alveoli
Millions of alveoli in the lungs provide a large moist surface area surrounded by capillaries for gas exchange.
5. Which mineral is essential for building strong bones and teeth (found in dairy products, leafy greens and small fish): calcium or sodium?
Calcium
Calcium phosphate gives bones and tooth enamel their hardness and strength.
6. Which dome-shaped muscle beneath the lungs contracts and flattens when you inhale, increasing chest volume and drawing air in: the diaphragm or the bicep?
Diaphragm
Contraction of the diaphragm and intercostal muscles expands the thorax, lowering pressure so air flows into the lungs.
7. Which microscopic blood vessels have walls only one cell thick to allow rapid exchange of oxygen, nutrients and waste with body tissues: capillaries or arteries?
Capillaries
Thin capillary walls provide a short diffusion pathway between blood and cells.
8. Why does the human stomach produce hydrochloric acid: to kill harmful bacteria and provide the acidic pH for pepsin (protease) enzymes, or to digest bones into gold?
To kill harmful bacteria and provide the acidic pH for pepsin (protease) enzymes
Stomach acid (pH ≈ 1.5–2) destroys pathogens and activates protease enzymes.
9. Which blood vessels carry blood BACK toward the heart and contain valves to prevent backflow: veins or arteries?
Veins
Veins operate at lower pressure and use one-way valves to keep blood flowing toward the heart.
10. Which muscular tube carries swallowed food from the mouth down to the stomach by wave-like contractions (peristalsis): the oesophagus (gullet) or the trachea (windpipe)?
Oesophagus (gullet)
Peristalsis in the oesophagus pushes the food bolus into the stomach.
11. Which organ produces bile (stored in the gallbladder) to neutralise stomach acid and emulsify fats into tiny droplets: the liver or the lungs?
Liver
The liver secretes alkaline bile, which emulsifies lipids to increase surface area for lipase enzymes.
12. In the human circulatory system, which blood vessels carry blood AWAY from the heart under high pressure with thick muscular walls: arteries or veins?
Arteries
Arteries have thick elastic and muscular walls to withstand high-pressure blood pumped from the heart.

12 questions · Seed 46 · Age guidance, not curriculum certification

Worksheet StudioPractice pack · Ages 13-15

Human body systems & organs

Take your time. Show your thinking.

1. Where does digestion begin in the human body through chewing and the action of salivary amylase: in the mouth or in the large intestine?
Heart · Lungs · Digestive Tract
2. Which nutrient group is primarily needed for building and repairing body cells and muscle tissue (found in fish, eggs, beans and lentils): proteins or water?
Heart · Lungs · Digestive Tract
3. Which class of digestive enzymes breaks down proteins into amino acids: proteases or amylases?
Heart · Lungs · Digestive Tract
4. What are the tiny air sacs in the lungs where oxygen diffuses into the blood and carbon dioxide diffuses out: alveoli or villi?
Heart · Lungs · Digestive Tract
5. Which mineral is essential for building strong bones and teeth (found in dairy products, leafy greens and small fish): calcium or sodium?
Heart · Lungs · Digestive Tract
6. Which dome-shaped muscle beneath the lungs contracts and flattens when you inhale, increasing chest volume and drawing air in: the diaphragm or the bicep?
Heart · Lungs · Digestive Tract
7. Which microscopic blood vessels have walls only one cell thick to allow rapid exchange of oxygen, nutrients and waste with body tissues: capillaries or arteries?
Heart · Lungs · Digestive Tract
8. Why does the human stomach produce hydrochloric acid: to kill harmful bacteria and provide the acidic pH for pepsin (protease) enzymes, or to digest bones into gold?
Heart · Lungs · Digestive Tract
9. Which blood vessels carry blood BACK toward the heart and contain valves to prevent backflow: veins or arteries?
Heart · Lungs · Digestive Tract
10. Which muscular tube carries swallowed food from the mouth down to the stomach by wave-like contractions (peristalsis): the oesophagus (gullet) or the trachea (windpipe)?
Heart · Lungs · Digestive Tract
11. Which organ produces bile (stored in the gallbladder) to neutralise stomach acid and emulsify fats into tiny droplets: the liver or the lungs?
Heart · Lungs · Digestive Tract
12. In the human circulatory system, which blood vessels carry blood AWAY from the heart under high pressure with thick muscular walls: arteries or veins?
Heart · Lungs · Digestive Tract

12 questions · Seed 46 · Age guidance, not curriculum certification

Worksheet StudioAnswer key · Ages 13-15

Human body systems & organs

Answers and reasoning. Review before teaching.

1. Where does digestion begin in the human body through chewing and the action of salivary amylase: in the mouth or in the large intestine?
In the mouth
Teeth mechanically break down food while saliva begins digesting starch into maltose.
2. Which nutrient group is primarily needed for building and repairing body cells and muscle tissue (found in fish, eggs, beans and lentils): proteins or water?
Proteins
Proteins supply amino acids for growth and tissue repair.
3. Which class of digestive enzymes breaks down proteins into amino acids: proteases or amylases?
Proteases
Proteases (such as pepsin and trypsin) hydrolyse proteins into amino acids.
4. What are the tiny air sacs in the lungs where oxygen diffuses into the blood and carbon dioxide diffuses out: alveoli or villi?
Alveoli
Millions of alveoli in the lungs provide a large moist surface area surrounded by capillaries for gas exchange.
5. Which mineral is essential for building strong bones and teeth (found in dairy products, leafy greens and small fish): calcium or sodium?
Calcium
Calcium phosphate gives bones and tooth enamel their hardness and strength.
6. Which dome-shaped muscle beneath the lungs contracts and flattens when you inhale, increasing chest volume and drawing air in: the diaphragm or the bicep?
Diaphragm
Contraction of the diaphragm and intercostal muscles expands the thorax, lowering pressure so air flows into the lungs.
7. Which microscopic blood vessels have walls only one cell thick to allow rapid exchange of oxygen, nutrients and waste with body tissues: capillaries or arteries?
Capillaries
Thin capillary walls provide a short diffusion pathway between blood and cells.
8. Why does the human stomach produce hydrochloric acid: to kill harmful bacteria and provide the acidic pH for pepsin (protease) enzymes, or to digest bones into gold?
To kill harmful bacteria and provide the acidic pH for pepsin (protease) enzymes
Stomach acid (pH ≈ 1.5–2) destroys pathogens and activates protease enzymes.
9. Which blood vessels carry blood BACK toward the heart and contain valves to prevent backflow: veins or arteries?
Veins
Veins operate at lower pressure and use one-way valves to keep blood flowing toward the heart.
10. Which muscular tube carries swallowed food from the mouth down to the stomach by wave-like contractions (peristalsis): the oesophagus (gullet) or the trachea (windpipe)?
Oesophagus (gullet)
Peristalsis in the oesophagus pushes the food bolus into the stomach.
11. Which organ produces bile (stored in the gallbladder) to neutralise stomach acid and emulsify fats into tiny droplets: the liver or the lungs?
Liver
The liver secretes alkaline bile, which emulsifies lipids to increase surface area for lipase enzymes.
12. In the human circulatory system, which blood vessels carry blood AWAY from the heart under high pressure with thick muscular walls: arteries or veins?
Arteries
Arteries have thick elastic and muscular walls to withstand high-pressure blood pumped from the heart.

12 questions · Seed 46 · Age guidance, not curriculum certification