Chemical bonds should be the correct answer choice.
Answer;
Antibodies.
The human immune system fights infection by releasing antibodies.
Explanation;
The immune system acts to defend the body against pathogens such as viruses, bacteria and fungi that may cause a disease.
It does so using various types of mechanism, one is by the production of antibodies.
Antibodies are proteins that are produced by the B-cell and are used by the immune system to identify and neutralize pathogens.
These antibodies also activates proteins known as complements which assist in the killing of bacteria, viruses and the infected cells.
Answer: topoisomerases
Explanation:
Topoisomerases are enzymes that help overwind or underwind DNA. DNA double helix has high tedency to get winded again because of its structural characeristics.
During replication and transcription of DNA, DNA gets overwound in front of a replication fork. This enzyme stops the double helix of DNA from becoming too tightly bound in front of the replication fork as the DNA opens.
The given demonstartion shows the action of topoisomerases as it shows unwinding of of supercoiled strands of pipe (DNA), which is don eby topoisomerases in the DNA replication process.
Hence, the correct answer is topoisomerases.
Oil Coal and Natural Gas are the fossil fuels the USA has the most reserves of. Given that only one of them is on the answers Coal is the correct answer.
