Summer annuals are defined by which of the following traits?

Summer annuals are characterized by their life cycle, which is defined by their ability to germinate during the spring or summer seasons and complete their growth, flowering, and seed production before the onset of winter. This lifecycle is inherently tied to their survival strategy, allowing them to take full advantage of the warmer months for growth and reproduction.

These plants typically thrive in the warmer temperatures of summer, and as the seasonal temperatures drop with the approach of winter, they die off. This distinct cycle distinguishes summer annuals from other types of plants, such as perennials, which live for multiple years, or winter annuals, which germinate in late summer or fall, overwinter, and then complete their life cycle in spring.

The other traits mentioned do not accurately describe summer annuals, as they emphasize different growth habits or life cycles. Understanding the seasonal behavior of summer annuals helps in managing them effectively in agricultural and right-of-way pesticide applications.