The Organism -

Autotrophs (make their own food via photosynthesis).

Different tissues working for a specific function (e.g., the heart). The Organism

No organism exists in a vacuum. They are part of an : Autotrophs (make their own food via photosynthesis)

Scientists categorize every organism into three primary domains: The Organism

This guide breaks down —the fundamental unit of life—from its basic building blocks to how it survives in a complex world. 1. What Defines an Organism?