The hierarchy of biological organisation
The hierarchy of biological organisation

Multicellular organisms are organised in levels. Small structures combine to make larger ones, and each level has a particular function.
Step-by-step lessons on Edexcel IGCSE Biology Level of organisation. Each one builds up to exam-style questions. Start with the foundational cell biology and core content before moving on to the more data-heavy ecology, genetics and practical-skills topics, which carry a large share of the exam marks.