Both nitrogen-fixing mutualists and mycorrhizae are maintained by photosynthate from the host plant. Root hairs are temporary organs, which the plant abandons once nutrients in their proximity have been depleted. A great proportion of the total living matter on Earth is cellulose, produced by plants. The cellulose either passes through the animal's digestive system undigested or it is broken down by enzymes produced by microorganisms living in the digestive system. In termites and certain other insects, but not in vertebrate animals, it is broken down by enzymes produced by special glands in the insect's digestive system.
Micelles carry negative charges the bind cations .
Weathering takes place primarily in the A horizon.