What Does Blood Do

About this printable What Does Blood Do science reading passage, NGSS-aligned (Grades 3-5)

This 250-word reading passage introduces fourth-grade students to the essential functions of blood in the human body, aligned with NGSS 4-LS1-1 and the Disciplinary Core Idea LS1.A: Structure and Function. Students learn how blood serves as both a delivery and cleanup system, transporting oxygen from the lungs to cells throughout the body, carrying nutrients from digested food to provide energy, removing waste products, and helping fight germs that cause illness. The passage uses age-appropriate language and relatable examples to build foundational understanding of how internal body structures support survival, growth, and behavior. Audio-integrated features support diverse learners, while the simplified differentiated version ensures accessibility for students reading below grade level. The passage includes bolded key vocabulary terms with immediate definitions, helping students develop scientific literacy. Supplementary activities include comprehension questions, writing prompts, and graphic organizers that reinforce understanding of blood's multiple functions. This resource prepares students for hands-on investigations and class discussions about body systems, providing the background knowledge necessary for deeper exploration of how organisms' internal and external structures function to support life processes.

Written by Workybooks TeamPublished by Workybooks

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Sample passage and quiz from What Does Blood Do

Illustration of a red blood cell delivering oxygen and nutrients to cells. — Blood keeps cells healthy by delivering oxygen, nutrients, and removing waste.

Blood is a red liquid that flows through your body all the time. Blood has many important jobs that keep you alive and healthy. Without blood doing its work, your body could not survive.

One main job of blood is to carry oxygen—a gas your body needs to stay alive. When you breathe in, oxygen enters your lungs. Blood picks up this oxygen and delivers it to every part of your body. Your brain, muscles, and all your other parts need oxygen to work properly.

Blood also carries nutrients—the good parts of the food you eat. After your body digests food, blood picks up nutrients and delivers them to your cells. Cells are tiny living parts that make up your body. They need nutrients for energy to grow and do their jobs.

Blood works like a cleanup crew too. It carries waste—things your cells don't need—away from cells. Blood takes this waste to organs that remove it from your body. This keeps your cells healthy and working well.

Finally, blood helps fight germs that try to make you sick. Special parts in blood attack germs and help you get better when you are ill. Think of blood as a delivery truck and cleanup system working together to keep your whole body running smoothly.

Interesting Fact: Your heart pumps about 2,000 gallons of blood through your body every single day—that's enough to fill a small swimming pool!