Final answer:
The correct sequence for secondary succession in an oak and hickory forest following a forest fire is 'grass- shrubs- small trees- forest,' reflecting the typical progression from grasses to a mature forest climax community.
Step-by-step explanation:
The sequence of events that best describes secondary succession, particularly in an oak and hickory forest after a forest fire, would begin with the growth of pioneer species such as annual plants, followed by the establishment of grasses and perennials. With time, these plants will improve the soil conditions, allowing for intermediate species to grow; these include shrubs, pines, and young oak and hickory trees. Ultimately, the area will progress to a mature forest stage, which may take several decades or even over a century to reach an equilibrium state known as the climax community.
Based on the information provided and the sequence of vegetation development during secondary succession, option B ('grass- shrubs- small trees- forest') is the best description since it reflects the typical progression from grasses to shrubs and small trees, culminating in a forest. This pattern is consistent with the successional stages seen after disturbances like wildfires in oak and hickory forests.