Free SAT Practice Question

Botanists once assumed that in deserts the plants best at surviving drought would be those that grow slowly and hoard water, since rapid growth seems wasteful where rain is scarce. Yet a survey of one arid basin found that several of the most drought-resilient shrubs did the opposite: they grew quickly whenever a brief rain came, then went dormant. These fast growers used the rare wet spells to build deep roots and lay down reserves, so that by the time the next dry stretch arrived they were better provisioned than their slow, steady neighbors. The finding suggests that in such climates, enduring drought may depend less on conserving effort at all times than on ______

Which choice most logically completes the text?