Harvey is studying the turtles that live in a pond. his knowledge of ecology will be most useful for explaining which of these observations of the turtles?

His knowledge on ecology will be helpful in determining how the turtles interact with the environment. Ecology is the study of ecosystems, and turtles play an important role as a consumer.

My best logical guess is D. Why would the turtle have to go above the water. If their living in a pond, then studying them above water makes no sense. So it's most useful if they are remaining underwater for many minutes at a time then reach for the surface, so that's the answer most likely, but i have no idea.

So... D. A turtle may remain underwater for several minutes, but then surfaces for at least a brief moment.

you did not attach the discourse, but i assume it to be the discourse on the origin and basis of inequality among men (the original titile in french is: "discours sur l'origine et les fondements de l'inégalité parmi les hommes"), also know as "second discourse". in this discourse, jean-jacques rousseau emphasizes that private property is the basis of all inequalities.

therefore, what enabled the old regime to maintain as long as it did was private property.