An ecosystem is a group of animals and plants living in a specific region and interacting with one another and with their physical environment. Ecosystems (24) _______ physical and chemical components, such as soils, water, and nutrients. These components support the organisms living in the ecosystem.

Ecosystems can also be thought of as the interactions among (25)________organisms in a given habitat. These organisms may range from large animals to microscopic bacteria and work together in various ways. (26)________,one species may serve as food for another.

People are part of the ecosystems (27)________ they live and work. Human activities, such as housing developments and trash disposal, can greatly harm or even destroy local ecosystems. Proper ecosystem (28)_________ is crucial for the overall health and diversity of our planet. We must find ways to protect local ecosystems without stifling economic development.

(Adapted from www.embibe.com)

Read the following passage and mark the letter A, B, C, or D to indicate the correct option that best fits each of the numbered blanks from 24 to 28.