'Black death' is related to:

Which of the following pairs are not viral diseases?

Which of the following is a symptom of pneumonia?

Which bacteria are responsible for pneumonia?
$(i)$ $Streptococcus$ $typhi$
$(ii)$ $Haemophilus$ $influenzae$
$(iii)$ $Streptococcus$ $pneumoniae$
$(iv)$ $Haemophilus$ $typhi$

In which disease do the lips and fingernails of the patient turn from gray to bluish in color?

Which of the following is $Xanthomonas$ related to?