Final answer:
A seed is the most likely structure to survive and develop into a new plant if it landed on fertile soil due to its protective coating, nutrient storage, and dormancy capabilities that allow it to withstand harsh conditions and germinate when conditions are optimal.
Step-by-step explanation:
Among the options given, the structure most likely to survive if it blew onto the surface of a small rock surrounded by fertile soil would be the seed. Seeds are innovative evolutionary structures that provide numerous benefits for the survival and establishment of new plant individuals. Spores, sorus, and pollen are less likely to develop into a new plant without immediate favorable conditions, whereas seeds have adaptations that allow them to survive harsh environments and wait for optimal conditions to germinate.
Seeds protect the embryo from desiccation and provide a store of nutrients for the early growth of a new plant. They can maintain dormancy for extended periods, which allows them to survive until conditions become favorable for growth. In addition, seeds can be effectively dispersed across various distances and environments to avoid competition with the parent plant and find new areas to thrive.
Comparatively, spores are simpler structures that generally require immediate moisture to develop into new plants. While spores are equipped for dispersal, they are not as robust as seeds in terms of protecting and nurturing new plant growth. Therefore, a seed landing on fertile soil would have the highest chance of developing into a mature plant.