The trunk is the main stem of a tree. It supports the branches and is supported by the roots. The trunk layers include heartwood, sapwood, and cambium. The heartwood is the innermost layer. (International Society of Arboriculture. 2025. How Trees Grow https://isarmc.org/how_trees_grow)
The oval-shaped oral cavity located at the apex of the digestive tract and consisting of two parts: the vestibule and the oral cavity proper. (MeSH, 2024. Mouth. http://id.nlm.nih.gov/mesh/D009055)
