When sea otters are present in a kelp forest community, there are more than 12 species in the community. if sea otters are removed, there are 5–7 species that remain in the community. these data suggest that sea otters are:

A keystone species

Explanation:

Keystone species are the species that play an important role in maintaining the structure of the ecological community they live in and they do so by affecting the numbers and types of other organisms that are found in the same ecological community. A keystone species may not necessarily occupy the largest biomass or be the greatest in terms of productivity in the given community but the removal of keystone species has a huge impact on the survival of other species and hence, the term keystone is used. In the given example, the sea otters are also playing the role of keystone species in a kelp forest community as in their presence there are more than 12 species however once these species are removed, the number reduces down to 5-7.

Gravitational force i believe