Final answer:
Water is essential to ecosystems because it allows autotrophs to perform photosynthesis and sustains life processes for all organisms, particularly heterotrophs, through its role in metabolic activities and aerobic respiration.
Step-by-step explanation:
To explain why water is vital to sustaining a healthy ecosystem, we look at two specific statements. First, autotrophs require water to perform photosynthesis, which produces oxygen gas and sugars from inorganic matter, supporting the flow of energy through the ecosystem. This is vital since autotrophs are the primary producers within food chains.
Secondly, all organisms, including heterotrophs, depend on water to conduct life processes. Water is crucial for metabolic activities, and aerobic respiration, the most efficient type of respiration, requires oxygen, which heterotrophs obtain from water in aquatic systems or from air in terrestrial ecosystems.
It's evident that water's role in both the physical support of organisms and the chemical reactions within cells is what makes it indispensable for a healthy ecosystem.