Answer: A) are economically valuable services provided by natural systems
Explanation: The ecosystem consist of both the biological and physical elements or components in our environment.
The ecosystem services can be Simply defined as the direct and indirect benefits humans get from the ecosystem which contributes to our survival, quality of life and general wellbeing. This services are essential to our daily lives,
It is categorised into four (4) services namely;
---Regulating services:- these are simply services that control natural processes . ( Water purification, pollination, waste management, soil formation etc.)
---Provisioning services; these are the products and goods gotten from the ecosystem ( food, medicine, fibre, woods, fresh water etc)
---Supporting/Habitat services; these type of services maintain other ecosystem services ( habitat, soil nutrients etc)
Cultural services; these are the non material benefits from the ecosystem ( spirituality, inspiration, beliefs etc)
So ecosystem services are economically valuable services provided by natural systems.