The option which is an example of a concrete statement is <span>A ) My future goals include getting my zoology degree and working at Woodland Zoo as a zookeeper. This person knows exactly what they want to do when they grow up - there is a specific job position that this person would like to work at, whereas the remaining options are pretty vague - they are not as concrete or specific as the first option is. </span>
O B. By putting each action in order from least harmful to the environment to most harmful.
A chronological structure refers to the arrangements of events in the manner or order they occurred or happened. In other words, it means the ordering of events in a sequence, like from beginning to end without any to and fro movements.
In the back cover description, the author mentions how some normal acts of human beings are significant causes of the environment. And to convey the same information using a chronological structure, the author can put each action in the order from least harmful to most harmful, in an orderly manner.