What defines an "annual" plant?

An "annual" plant is defined by its lifecycle, which is completed in a single growing season. This means that from germination to seed production, the entire process occurs within one year. Annual plants typically grow quickly, flower, produce seeds, and then die all within this short timeframe. Examples of annual plants include marigolds, zinnias, and many vegetables such as tomatoes and lettuce.

The other definitions offered do not align with the characteristics of annual plants. For instance, plants that live for more than two years are classified as perennials, not annuals. Similarly, while some annuals may flower multiple times during their short life cycle, the defining characteristic is the completion of their lifecycle within a single season. The claim about sunlight is not relevant to the definition of annuals, as all plants, regardless of their lifespan, generally require some amount of sunlight to grow.