Question

what does it mean when an element has been sequestered?
it completely disappears.
it is released into the air.
it is turned into energy.
it is isolated in a stable form.

Explanation:

In environmental science, when an element is sequestered, it means it is isolated in a stable form. For example, carbon sequestration involves capturing and storing atmospheric carbon dioxide. The other options are incorrect. An element cannot completely disappear (violates conservation of mass), being released into the air is the opposite of sequestration, and elements are not typically turned into energy in this context.

Answer:

It is isolated in a stable form.