There are a lot of forms of inteligence and the issue is more complex, if we account the needs and challenges of the different eras which ignite the causes of our evolution.
I dare to say that in a parallel analogy of the above Ages, which mentioned as "thoughts" are proceeding at a vertical axis. An other example and interesting triplet but this time at horizontal axis, is at Homers Illiad:
Who was the smarter, -Odysseus, Palamedes, or Nestor ? - for example.
The one returned home relatively difficult, the other died dishounoured under conspiracy, and the last returned relatively easy.
While the first (as thoughts)are part of our collequial heritage, the second its the case about the individual aspect of the theme.
How different personalities respond to critical issues under stressfull conditions.
Maybe for various reasons is not the perfect example,-at least for the era we are talking- for the reason that: Being so"smart" it is not the best skill which if not disgraced, at least some features of it considered as second class (Μήτις). Being brave is the absolut criteria of the case, and the grand prize is the Fame.
A lot men fall under the great walls of Troy but few the names we remember...
Τhere many words for "smartness" to remind us, as well that there are many kinds of it ,at many languages I suppose, but the modern version of being "smart" is relatively new, I would say is -one of- the foundation stone of the Industrial Revolution; Smart phones, cars, gadgets, fabrics etc etc. Which certainly the smart has the mean of "functional".
Today we are experiencing the third; or fourth age of that revolution; If iam not wrong we are leaving us behind the post-modern and we are heading to a new, unnamed at the moment -widely accepted- to described the socially symbiotic consequenceses with the so famous AI devices.
But that is the concept of the "fourth thought" and the five horses of apocalypse... Which I will deploy maybe later.
I consider that behind that tricky guestion, -if inteligence is hereditary....etc. -the core issue is, that: if genes; or enviroment;-are responsible for the "smartness event" and to what scale.
I also consider that to define what smart is, its an other subject as well that: at what level, that smartness inherited.
At a parallel analogy of inteligence, is the case of having the good looks -other words beauty. I will avoid the word physical appearence because physical-parts- are the brains; also. Anyway, both cases are inherited from our ancestors we like it or not, but in the case of beauty we clearly -objectivelly- we have to deal with the fact that:
Two -very- beautifull parents, do not necessery having beautifull children. Allthough all our physical appearence is absolut result of our parents.
if intelligence is heritated and as a result is determined -somehow;- from dna, as well the physical beauty, maybe is not necessery Intelligent parents to have intelligent kids.
Anyway sometimes I have the feeling that "enviroment" is the 51% factor of all cases.