The answer to fill the blanks would be:
25 percent of parents reported spanking their children frequently, with different reasons ( most common one is to enforce discipline to their children when they do something wrong ).
Hope my answer has come to your help.
There are many, but the major ones are that
1) language is somehow saved in our genes, which means that people with better communication skills had a survival advantage over those that didn't and that language is innate. This usually means that the specific parts of language: syntax for example are innate too
2) language was "invented" like writing: and then it was transmitted and changed.
