What is a characteristic of annual plants?

Annual plants are defined by their ability to complete their entire life cycle, from germination to seed production, within a single growing season. This characteristic allows them to grow, flower, and produce seeds quickly in response to environmental conditions before dying off as the season changes.

The other options relate to different plant life cycles. The statement that they live for multiple years describes perennial plants, not annuals. The notion that they flower only once applies to some species but does not define all annuals, as some may produce multiple blooms within a season. The idea that annual plants only grow in tropical climates is inaccurate, as annuals can thrive in various climates, including temperate regions. Therefore, the characteristic that accurately represents annual plants is their ability to complete their life cycle within one growing season.