Final answer:
In options b, c and d, the revisions, the comma splices and fused sentences have been corrected by separating independent clauses into distinct sentences or using appropriate conjunctions. The correct options are b, c and d.
Step-by-step explanation:
b) A human disease from almost seven hundred years ago made headlines again recently in 2011. Scientists reported reconstructing the DNA of the bacterium responsible for the Black Death of 1347-1351. By 1400, at least five additional outbreaks had followed; about 25 million people, roughly a third of Europe's population at the time, had died from the Black Death.
c) A human disease from almost seven hundred years ago made headlines again recently in 2011. Scientists reported reconstructing the DNA of the bacterium responsible for the Black Death of 1347-1351. By 1400, at least five additional outbreaks had followed. About 25 million people, roughly a third of Europe's population at the time, had died from the Black Death.
d) A human disease from almost seven hundred years ago made headlines again recently in 2011. Scientists reported reconstructing the DNA of the bacterium responsible for the Black Death of 1347-1351. By 1400, at least five additional outbreaks had followed; about 25 million people, roughly a third of Europe's population at the time, had died from the Black Death.
In these revisions, the comma splices and fused sentences have been corrected by separating independent clauses into distinct sentences or using appropriate conjunctions.