Answer: Micro-organisms
Explanation: Micro-organisms, earthworms and insects help break down crop residues and manures by ingesting them and mixing them with the minerals in the soil, and in the process recycling energy and plant nutrients. Sticky substances on the skin of earthworms and those produced by fungi and bacteria help bind particles together.
The correct answer is C. Many Americans began to worry about nuclear power.
Explanation:
In March of 1979, one of the reactors in a nuclear plant located in Three Mile Island, Pennsylvania (USA) caused a minor leak of radiation as this reactor melted. Soon, closer communities to the plant and the general public in the U.S. showed their concerns about nuclear power and its safety.
Indeed, this accident was the most serious in the country and made many citizens end their support for the use of nuclear power. Also, many families left the area because they were afraid of the consequences of the radiation that escaped, and anti-nuclear groups led protests and legal actions. Fortunately, the amount of radiation was not high and sometime after the accident, it was shown radiation did not have any important negative effect. Thus, this accident made that "many Americans began to worry about nuclear power."
