Which phrasE bEst dEscribEs an EcosystEm?

a. aLL Living things and thE pLacEs on Earth whErE thEy arE found
b. organisms intEracting with Each othEr and with nonLiving things in a cErtain rEgion
c. thE variEty of organisms on Earth or in a particuLar arEa of thE biosphErE
d. a group of Living things that can intErbrEEd to rEproducE