Fire is an example of energy changing one form to another. It is used as thermal energy (for heating and warmth) and for burning energy.
The other options don't really have any energy.
An ecosystem is defined as a place where organisms interact with one another and with their physical surroundings. The most common phosphorus reservoir in the ecosystem is the sedimentary rock. Add to that, it is believed that phosphorus cycle actually starts in these types of rocks. Through the process of weathering, phosphates are being carried by the rain or water and are dispersed to the soil and different bodies of water. Plants become reservoirs, as well, because they latch o<span>n the phosphate ions from the soil.</span>
2nd choice is the correct one
