# Cells, Tissues & Organs

Understand that the body is organised in a hierarchy: tiny cells are the building blocks, groups of similar cells form tissues, tissues combine into organs (like the heart or stomach), and organs work together in organ systems (like the circulatory system)

Builds on: The Heart & Blood (soft, https://ai.page/c/the-heart-and-blood/en.md), The Brain Controls the Body (soft, https://ai.page/c/the-brain-controls-the-body/en.md), How Breathing Works (soft, https://ai.page/c/how-breathing-works/en.md)

Concept id: cells-tissues-and-organs. Subject: science. Licence: CC BY-SA 4.0.

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