The r-type strain of s. pneumoniae does not cause pneumonia because bacterial cells are g

The R-Type strain of s. pneumoniae does not cause pneumonia because the bacteria cells do not have a protective coating. When it enters the host, it cannot withstand the attacks of the immune system thus it dies before infection. On the other hand, the S-type strain has a protective coat that allows it to survive in the host, which causes infection.

There are  advantages  to being  multicellular  rather than unicellular. these include allowing: the  organism  to be larger.