In both cases, however, the adaptation is secondary to the primary purpose of the DTD — that is, if you are primarily authoring books, it makes the most sense to use a DTD that is designed for books.
Plant secondary metabolites is an adaptation of plants to circumstances, and its result of plant interacting with biotic factor and abiotic factor in the permanent evolution.
植物次生物质是植物对环境的一种适应，是在长期进化过程中植物与生物和非生物因素相互作用的结果。
3
Many vessel numbers, small pore, libriform fibres (mechanical tissue)and obvious secondary thickening of xylem tissue are the features of adaptation to the environment.