Period


Punctuation (p)
Proper punctuation provides readers the ability to pause.  If not, they would be out of breath very soon.  Placing a punctuation mark in its proper place takes some effort.  Many students often complain that they have a hard time putting in commas.
End Punctuation
A period, question mark, and exclamation denote the end of a statement.
Period (.)
Periods are used to end a statement, a mild command, an indirect question, or most abbreviations, as shown in these examples. 
Zinnias grow well in the summer heat.
Take the garbage to the curb.
 asked if the house was on sale.
(Some abbreviations):  Mr., Mrs., Ms.  Dr., B.A., M.A., Ph.D., a.m., p.m.,
                                       Rd., St., e.g., i.e.
Avoid putting periods in acronyms, as these:  USA, FBI, IRS, UNO, TN, USM, FDA, CDC, NAACP, NFL.