Question

Which civilization is said to be the "Mother Culture" of Central America

Answer 1

The Olmec. There's even a book on the subject at Amazon:

The Olmec: Mother Culture of Mesoamerica
http://www.amazon.com/The-Olmec-Mother-Culture-Mesoamerica/dp/0847810445

...and a Washington Post science article on the Olmec:
http://www.washingtonpost.com/wp-dyn/articles/A32926-2005Feb17.html

Answer 2

thank you :D