Typhoid and tetanus are caused by .....

$Yersinia pestis$ is responsible for:

What is $Streptococcus \text{ } pneumoniae$?

$Salmonella$ $typhi$ generally enter the small intestine through.........and migrate to other body parts through....... . The correct combination to fill the blanks is

Different species of the bacterium $Mycobacterium$ cause:

In the disease $Pneumonia$,which fluid-filled secretion acts as a culture medium for the pathogenic bacteria?