Classify each item as contributing to the spread of the black death or an effect of the epidemic

Lack of sanitation, ineffective treatments, and increase of rats and fleas are the contributors. The other three are the effects.

Contibutor:

Effect:

Explanation:

The black plague, bubonic plague or black death was a pandemic of plague that ravaged Europe during the fourteenth century and was transmitted by fleas transported by rodents (rats, gerbils, squirrels). However, it is also believed that transmission between people is produced by human ectoparasites, such as the common flea or body lice. It is believed that the epidemic emerged in Central Asia, from where it passed to Italian cities with great maritime activity such as Genoa, and from there to all of Europe. The Black Death ended with more than a third of the European population and some 45 million people worldwide.

It reached its peak between 1346 and 1361. Diane Zahler estimates that mortality exceeded a third, perhaps 40% of Europeans, or what is the same, would have killed 20 of the 50 million European inhabitants. It was the cause of death of approximately 45 to 50 million people between the first cases in Mongolia (1328) and the last ones in European Russia (1353). This disease devastatingly affected Europe, China, India, the Middle East and North Africa, not affecting sub-Saharan Africa or the American continent.

the doctrine of nullification recommended that states living inside the union have the one-sided, inalienable ideal to void any law made by the national government that could be esteemed illegal.

the united states was shaped based on a general agreement among its individual states. hence, it is inferred that under the hypothesis of invalidation, since the states are the establishment of the union, they have the ability to referee and disprove unlawful laws.

radioactive dating, also known as  radioisotope dating  is a process that in  estimating the approximate  age  of  rocks. these data can be analyzed from  the studies dealing with the  decay of the radioactive elements that are present in these rocks. in nature, there are a few types of materials or atoms which are quite unstable and they spontaneously decay or breakdown to form other kinds of atoms.