How does the passage expand on the central idea
"large numbers of elizabethans died from illness and
disease"?
serious though influenza and malaria are, they are not
the biggest killers of the age. that title belongs to the
plague or "pestilence." no one knows precisely how many
die over the course of the reign but the total is probably
around 250,000. in 1565 the people of bristol count up
the plague victims for that year and arrive at the figure of
2,070, almost 20 percent of the population. ten years
later, after another deadly outbreak, they record a further
2,000 fatalities.
- the time traveler's guide to elizabethan england,
ian mortimer
it specifies that malaria was the most dangerous
disease in elizabethan england.
it clarifies that the plague was the biggest killer in
elizabethan england.
it explains the causes of illnesses such as
influenza, malaria, and the plague
it lists the ways to avoid falling ill with plague,
influenza, and malaria.

b

It clarifies that the plague was the biggest killer in Elizabethan England.

Explanation:

The bubonic plague spread to London throughout the Elizabethan age, more than two hundred years during the pandemic in the 14th century. The most significant outbreaks occurred in 1563, 1593, 1603, 1625, and 1665, with several occurrences. Elizabethan was a gloomy, grim, scary place to live during most of the outbreaks.

Approximate 100,000 citizens have been killed by the pandemic, which was dubbed The Big Plague of London in 1665. This began in May 1665 and destroyed the town until the great storm in London of Sept of the same year. Most rats and fleas carrying bacteria were destroyed by fire.

the present continuous is a verb tense which is mainly used to indicates that an action is in progress at the moment of speaking.  

it is formed using: person + verb to be (am/is/are) +verb + - ing form  

example: i am studying at this moment .

in addition, the present continuous is also used in order to express things that will or will not happen in the near future.

example: i am having dinner with some friends tonight.

the speaker sometimes   uses it   to express that an action is repeated and it causes irritation on the part of the speaker

example: my sister is constantly complaining about everything.