Final answer:
Ecosystem capital includes both tangible goods such as food and materials, and vital ecosystem services like water purification, which natural resources alone may not encompass.
Step-by-step explanation:
The phrase "ecosystem capital" is favored over "natural resources" because it encompasses not only the tangible goods that ecosystems provide, such as food, materials, and medicinal plants, but also the essential ecosystem services that support life on Earth. These services include water purification, air oxygenation, climate regulation, and pollination, among others. By valuing both the goods and services, ecosystem capital reflects the full range of benefits that ecosystems offer to humanity and underlines the necessity of incorporating these values into decision-making processes for the sustainable management of natural assets.