Compared to the spheres, which of the following has "the hardest boundaries to pin down"?
A) atmosphere
B) biosphere
C) lithosphere
D) hydrosphere
E) All of the above: they are equally imprecise.

Question

Quizplus · Accepted Answer

The biosphere is the area in which all living organisms exist, which makes it difficult to define its exact boundaries. It is influenced by the other spheres (atmosphere, lithosphere, and hydrosphere), but it is also influenced by human activities and ecological interactions that can blur its borders. Therefore, it has the hardest boundaries to pin down.

Compared to the Spheres, Which of the Following Has "The