Ecosystem services are services provided by
a.
the government in order to maintain ecosystem health
b.
communities in an effort to beautify local neighborhoods
c.
organizations committed to the environment
d.
nature that benefit mankind

The answer is D. Ecosystem services are services provided by nature that benefit mankind.  An ecosystem service is any positive and varied benefit that people freely gain from wildlife or ecosystems. These are grouped in to four major categories which are provisioning, regulating, supporting and cultural. These services are offered by the environment to us. An example can be forest ecosystems, that provided us any kind of fruits, plants, wood, etc. (provisioning service), the plants clear the air (regulating service).

worldwide, 780 million people do not have access to an improved water source. an estimated 2.5 billion people lack access to improved sanitation (more than 35% of the world's population)