Simplify the following text for a Grade 13 native English-speaking person.
Original: While the heritability of IQ has been investigated for nearly a century , controversy remains regarding the significance of heritability estimates , and the mechanisms of inheritance are still a matter of some debate .
Simplified: While its inheritance has been investigated for nearly a century , controversy remains as to how much is inheritable , and the mechanisms of inheritance are still a matter of some debate .