This document summarizes key concepts about plant structure, reproduction, development, and control systems from chapters 31 and 33: 1) Plants are divided into two main groups - gymnosperms which bear seeds in cones, and angiosperms or flowering plants which are the most diverse and bear seeds in flowers. Angiosperms are further divided into monocots and dicots which have structural differences. 2) Plant organs consist of specialized tissues and cell types that carry out functions like photosynthesis, transport, and support. Hormones like auxin, cytokinin, gibberellin, ethylene and ABA regulate growth, development, and response to the environment. 3) Primary and secondary