Body Systems and Senses — Answer Key
Part A: Fill in the Blank
Write the missing word or number on each line.
1. The circulatory system uses the heart to pump blood through the body.
Grade 4 science teaches that the circulatory system moves blood through vessels to deliver oxygen and nutrients.
2. The respiratory system uses the lungs to take in oxygen and release carbon dioxide.
In Grade 4, students learn that the respiratory system handles breathing through the lungs.
3. The digestive system breaks food down so the body can use its nutrients.
Grade 4 science explains that the digestive system processes food in the stomach and intestines.
4. The skeletal system is made of bones that support and protect the body.
Grade 4 students learn that the skeletal system gives the body its shape and protects organs like the brain.
5. The muscular system uses muscles that pull on bones to make the body move.
In Grade 4 science, the muscular system works with the skeletal system to produce movement.
6. The nervous system uses the brain and nerves to control the whole body.
Grade 4 students learn the nervous system carries signals and controls thinking, senses, and movement.
7. The heart is the main organ of the circulatory system.
Grade 4 science identifies the heart as the pump that powers the circulatory system.
8. The stomach is part of the digestive system because it helps process food.
Grade 4 students learn that the stomach mixes food with acids and is part of the digestive system.
9. Bones in the skeletal system also help make blood cells inside the marrow.
In Grade 4 science, the skeletal system supports the body and makes blood cells in bone marrow.
Part B: Matching
Match each item on the left to the correct answer on the right.
1. Match each item to its correct answer.
Heart
→ Circulatory system organ that pumps blood
Circulatory system organ that pumps blood
Lungs
→ Respiratory system organ that takes in air
Respiratory system organ that takes in air
Stomach
→ Digestive system organ that breaks down food
Digestive system organ that breaks down food
Brain
→ Nervous system organ that controls the body
Nervous system organ that controls the body
Grade 4 science expects students to connect key organs with their body systems and main functions.