How many of the following statements are true regarding prokaryotic ribosomes?

a) Are associated with the plasma membrane of the cell.

b) Are 15 nm by 20 nm in size.

c)Contain two subunits, the larger 50S and the smaller 30S subunit 

d) The larger and smaller subunits together form 80s ribosome.

Ribosomes are non-membrane bound structures involved in protein synthesis.They translate the mRNA into proteins.

a) are associated with the plasma membrane of the cell.

b) are 15 nm by 20 nm in size.

c)contain two subunits, the larger 50S and the smaller 30S subunit.

d) The larger and smaller subunits together form 70s ribosome.