Elephants, who are important grazers, are instrumental in transforming woodlands into grasslands. This has a tremendous impact on other species that depend on the grass for their survival. The significance of the elephant in this example is B. keystone species.
The planetary body that Spirit was designed to explore the wide ranges of soil and rocks for clues of the water activity on Mars. Spirit specifically landed at the Gusev Crater which was before, a possible lake in a giant crater.
