c) are economically valuable services provided by natural systems is the correct answer.
Explanation:
Ecosystem services are methods that happen in an ecosystem.
Ecosystem services are the abundance of advantages that nature gives to society and humankind.
Ecosystem services make the individual life pleasant via producing nutritious food and cleaned water, controlling disease, oxygen generation, soil formation, biomass production and giving social and spiritual advantages.
I believe this is it The centripetal force is given by F = mv^2 / r When v' = v/2, F' = mv'^2/r = m(v/2)^2/r = mv^2/4r = F/4. So the centripetal force is divided by 4.
