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Primary 5 Science: Human System — Respiratory and Circulatory Systems / Integration Practice
Real Primary 5 Science questions on Human System — Respiratory and Circulatory Systems / Integration, pulled directly from the Olibits question bank — the same questions a child would actually see, not separately written for this page.
Curriculum alignment
Science Teaching & Learning Syllabus, Primary Three to Six (MOE, 2023 syllabus)
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Real Human System — Respiratory and Circulatory Systems / Integration practice questions
During vigorous exercise, why do a person's heart rate and breathing rate increase together?
Exercising muscles need more oxygen and nutrients from the blood to release energy, and produce more carbon dioxide that must be removed via the lungs, so the heart and lungs work harder together ✓
The digestive system signals the heart to slow down and conserve energy
The heart and lungs increase activity only to help the skeletal system grow taller
Breathing rate rises only to cool the body down, unrelated to the heart
Working muscles respire faster and need more oxygen and nutrients while producing more carbon dioxide, so the heart beats faster to circulate blood and the lungs work harder to exchange gases, showing the circulatory and respiratory systems responding together.
The heart's pumping action moves blood in a continuous loop around the body. How does this support the work of the respiratory and digestive systems?
It produces oxygen directly, replacing the need for lungs
It digests food that has already passed through the lungs
It pushes blood to the lungs to collect oxygen and to the intestines to collect nutrients, then delivers both to body cells ✓
It stops the digestive and respiratory systems from working during rest
The heart pumps blood to the lungs, where it picks up oxygen, and past the intestines, where it picks up digested nutrients, then delivers both to cells throughout the body.
If the circulatory system suddenly stopped transporting oxygen to body cells, what would most likely happen?
Body cells would only be affected if they were in the arms or legs
Cells would not get enough oxygen for respiration, and organs could fail from lack of energy ✓
Cells would begin producing their own oxygen instead
The digestive system would take over the role of transporting oxygen
Nearly all body cells rely on a continuous oxygen supply from the blood to carry out respiration and release energy; without it, cells cannot function properly, leading to organ damage or failure.
Carbon dioxide produced by muscle cells during respiration must be removed from the body. Which two systems work together to achieve this, and in what order?
The circulatory system carries carbon dioxide from cells to the lungs, then the respiratory system removes it from the body by exhaling ✓
The excretory system carries carbon dioxide to the kidneys, then the digestive system removes it
The respiratory system carries carbon dioxide to the cells, then the circulatory system stores it permanently
The digestive system breaks carbon dioxide down into oxygen for reuse
Carbon dioxide diffuses from body cells into the blood, which the circulatory system carries to the lungs; the respiratory system then removes it from the body when we exhale.