Is there any text along with the paper such as a book or article.
The synonym that describe the greatest degree of regret would be : D. Repentant : Feeling remorse to a degree marked by an extreme change
For example, people who felt repentant because he tend to scam other people make a drastic change and decided to became a monk in Asian continent
hope this helps
Prions are a type of defective proteins, that can cause normal proteins to turn into defective, infectious ones: prion, word that comes from the term "proteinaceous infectious particle"; prions can cause neurodegenerative diseases. Unfortunately, even after scientists identified prions as the causal agents of the "mad cow" disease and others like the "kuru" (discovered in New Guinea, amongst a tribe that practiced cannibalism) and the "scrapie", the authorities tried to hide the epidemic, they took too long to ban the feeding of animals with mixes that included proteins from infected animals, so if authorities had implemented more actions since at least 1993 perhaps the epidemic could have been controlled earlier, instead of almost 25 years after the disease was identified.
In this sense, the author takes us step by step in the process (over time) and illustrates how people got frustrated because of the reaction of the government: nothing was done about the disease until over ten years after its discovery.