Populations of aspen trees in the western united states are being destroyed by an unexpected illness. The altered landscape is affecting the animals that live there. Populations of deer mice are increasing greatly in these areas. Unfortunately, these mice carry a disease which can be fatal in humans. This scenario best illustrates... a. The stability of the ecosystem is limited by the amount of water available b. Every population in an ecosystem is linked with other populations c. Ecosystems do not need a constant source of energy d. The altered landscape will always result in a disease due to biotic factors

An ecosystem is a biological term which refers to all the biotic and abiotic factors present in a particular area which interacts with each other directly or indirectly and affect each other.

In the given case, the interactions and the direct or indirect dependency of the population to each other have been shown as the Aspen trees population which are destroyed by the illness leads to the increase in the population of deer mice. The increase in the population of deer mice can lead to the destruction of the human population as they carry a disease for humans.

Since one population is linked to others directly or indirectly, therefore, the selected option is correct.