What type of plant completes its life cycle in one season?

Annual plants are characterized by their ability to complete their entire life cycle within a single growing season. This includes germination, growth, flowering, and producing seed, all within a period that typically lasts from one spring to the first frost of the following autumn. After they have produced seeds, annual plants typically die off, ensuring their species can continue through the seeds that have been dispersed.

In contrast, biennial plants take two seasons to complete their life cycle, germinating in the first year and typically flowering and producing seeds in the second year before dying. Perennial plants, on the other hand, live for multiple seasons and generally flower and produce seeds year after year, returning each spring after going dormant in the winter. Deciduous plants refer to a category that drops their leaves seasonally, but this term does not specifically address the plant's life cycle length and is not directly related to how long it takes for them to complete their life cycle.

Thus, annual plants are specifically defined by their life cycle completion within a single season, making them the correct answer.