Biology (B)

Introduction

Where does the water come from that is needed by your cells? Or the carbon and nitrogen that is needed to make your organic molecules? Unlike energy, matter is not lost as it passes through an ecosystem. Instead, matter is recycled. This recycling involves specific interactions between the biotic and abiotic factors in an ecosystem.

CK-12 Foundation, Biology. http://creativecommons.org/licenses/by-nc-sa/3.0/