Lesson 5 of 13 · 7 min

Cells: the building blocks of life

All living things are made of cells — tiny units of life. Some living things are a single cell; others, like us, have trillions. Cells group into tissues, tissues into organs (like the heart), and organs into systems.

🦠 → 🟨 → 🧑

Cells → organs → whole body

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