The ecosystem with the greatest sustainability will be the one that has the

Greatest variety of different organisms.

Explanation:

Different organisms or animals

Explanation: In a ecosystem, if you have different animals or organisms, it give them a better chance of survival, reason being that they can choose to eat whatever animal or organism they want because there is lots of animals to choose from the ecosystem. Basically the more diversity you have, the better chance you will survive, and the less diversity you have, the less chance of survival.

explanation:

for  example, forests have higher evapotranspiration than other ecosystems,  such  as grasslands, because of their deeper roots and greater leaf area. thus forests have a net moistening effect on the atmosphere and become a moisture source for downwind ecosystems.

currents is the correct answer.