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.

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Age band:Ages 10-12 Ages 13-15

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Worksheet StudioPractice pack · Ages 13-15

Human body systems & organs

Take your time. Show your thinking.

1. Which mineral is required to make haemoglobin in red blood cells (so deficiency leads to anaemia): iron or iodine?
Heart · Lungs · Digestive Tract
2. Which digestive enzyme breaks down large starch molecules into simple sugars: amylase or lipase?
Heart · Lungs · Digestive Tract
3. 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
4. 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
5. Which class of digestive enzymes breaks down proteins into amino acids: proteases or amylases?
Heart · Lungs · Digestive Tract
6. Which component of human blood contains haemoglobin and transports oxygen from the lungs to body tissues: red blood cells or platelets?
Heart · Lungs · Digestive Tract
7. Which tiny cell fragments in blood help form clots at a wound to stop bleeding: platelets or red blood cells?
Heart · Lungs · Digestive Tract
8. What is the straw-coloured liquid portion of blood that transports dissolved glucose, carbon dioxide, urea and hormones: plasma or bile?
Heart · Lungs · Digestive Tract
9. 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
10. Which nutrient group serves as the body’s primary fuel for cellular respiration (found in rice, bread, pasta and fruit): carbohydrates or minerals?
Heart · Lungs · Digestive Tract
11. Which vitamin found in citrus fruits and fresh vegetables prevents scurvy and supports healthy connective tissue: Vitamin C or Vitamin D?
Heart · Lungs · Digestive Tract
12. What is the main function of the large intestine (colon): to absorb remaining water from undigested food waste, or to pump blood?
Heart · Lungs · Digestive Tract

12 questions · Seed 44 · 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. Which mineral is required to make haemoglobin in red blood cells (so deficiency leads to anaemia): iron or iodine?
Iron
Iron sits at the core of the haem group in haemoglobin that binds oxygen.
2. Which digestive enzyme breaks down large starch molecules into simple sugars: amylase or lipase?
Amylase
Carbohydrases such as amylase catalyse the breakdown of starch into sugars.
3. 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.
4. 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.
5. 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.
6. Which component of human blood contains haemoglobin and transports oxygen from the lungs to body tissues: red blood cells or platelets?
Red blood cells
Red blood cells (erythrocytes) are packed with haemoglobin and lack a nucleus to maximise oxygen transport.
7. Which tiny cell fragments in blood help form clots at a wound to stop bleeding: platelets or red blood cells?
Platelets
Platelets trigger blood clotting to seal damaged vessels.
8. What is the straw-coloured liquid portion of blood that transports dissolved glucose, carbon dioxide, urea and hormones: plasma or bile?
Plasma
Blood plasma is the liquid matrix in which blood cells are suspended.
9. 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.
10. Which nutrient group serves as the body’s primary fuel for cellular respiration (found in rice, bread, pasta and fruit): carbohydrates or minerals?
Carbohydrates
Carbohydrates are broken down into glucose, the main fuel for cellular respiration.
11. Which vitamin found in citrus fruits and fresh vegetables prevents scurvy and supports healthy connective tissue: Vitamin C or Vitamin D?
Vitamin C
Vitamin C (ascorbic acid) is essential for collagen synthesis and immune health.
12. What is the main function of the large intestine (colon): to absorb remaining water from undigested food waste, or to pump blood?
To absorb remaining water from undigested food waste
The large intestine reabsorbs water and electrolytes, leaving semi-solid faeces.

12 questions · Seed 44 · Age guidance, not curriculum certification

Worksheet StudioPractice pack · Ages 13-15

Human body systems & organs

Take your time. Show your thinking.

1. Which mineral is required to make haemoglobin in red blood cells (so deficiency leads to anaemia): iron or iodine?
Heart · Lungs · Digestive Tract
2. Which digestive enzyme breaks down large starch molecules into simple sugars: amylase or lipase?
Heart · Lungs · Digestive Tract
3. 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
4. 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
5. Which class of digestive enzymes breaks down proteins into amino acids: proteases or amylases?
Heart · Lungs · Digestive Tract
6. Which component of human blood contains haemoglobin and transports oxygen from the lungs to body tissues: red blood cells or platelets?
Heart · Lungs · Digestive Tract
7. Which tiny cell fragments in blood help form clots at a wound to stop bleeding: platelets or red blood cells?
Heart · Lungs · Digestive Tract
8. What is the straw-coloured liquid portion of blood that transports dissolved glucose, carbon dioxide, urea and hormones: plasma or bile?
Heart · Lungs · Digestive Tract
9. 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
10. Which nutrient group serves as the body’s primary fuel for cellular respiration (found in rice, bread, pasta and fruit): carbohydrates or minerals?
Heart · Lungs · Digestive Tract
11. Which vitamin found in citrus fruits and fresh vegetables prevents scurvy and supports healthy connective tissue: Vitamin C or Vitamin D?
Heart · Lungs · Digestive Tract
12. What is the main function of the large intestine (colon): to absorb remaining water from undigested food waste, or to pump blood?
Heart · Lungs · Digestive Tract

12 questions · Seed 44 · Age guidance, not curriculum certification

Worksheet StudioAnswer key · Ages 13-15

Human body systems & organs

Answers and reasoning. Review before teaching.

1. Which mineral is required to make haemoglobin in red blood cells (so deficiency leads to anaemia): iron or iodine?
Iron
Iron sits at the core of the haem group in haemoglobin that binds oxygen.
2. Which digestive enzyme breaks down large starch molecules into simple sugars: amylase or lipase?
Amylase
Carbohydrases such as amylase catalyse the breakdown of starch into sugars.
3. 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.
4. 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.
5. 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.
6. Which component of human blood contains haemoglobin and transports oxygen from the lungs to body tissues: red blood cells or platelets?
Red blood cells
Red blood cells (erythrocytes) are packed with haemoglobin and lack a nucleus to maximise oxygen transport.
7. Which tiny cell fragments in blood help form clots at a wound to stop bleeding: platelets or red blood cells?
Platelets
Platelets trigger blood clotting to seal damaged vessels.
8. What is the straw-coloured liquid portion of blood that transports dissolved glucose, carbon dioxide, urea and hormones: plasma or bile?
Plasma
Blood plasma is the liquid matrix in which blood cells are suspended.
9. 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.
10. Which nutrient group serves as the body’s primary fuel for cellular respiration (found in rice, bread, pasta and fruit): carbohydrates or minerals?
Carbohydrates
Carbohydrates are broken down into glucose, the main fuel for cellular respiration.
11. Which vitamin found in citrus fruits and fresh vegetables prevents scurvy and supports healthy connective tissue: Vitamin C or Vitamin D?
Vitamin C
Vitamin C (ascorbic acid) is essential for collagen synthesis and immune health.
12. What is the main function of the large intestine (colon): to absorb remaining water from undigested food waste, or to pump blood?
To absorb remaining water from undigested food waste
The large intestine reabsorbs water and electrolytes, leaving semi-solid faeces.

12 questions · Seed 44 · Age guidance, not curriculum certification