Why is it often difficult to differentiate between heredity and environment when it comes to intelligence? (psych)

It becomes difficult to differentiate difficult to differentiate between heredity and environment when it comes to intelligence because there have been evidences like -

Hereditical evidences-

a) The generations of an high IQ person posses high IQ.

b) Siblings have high level of similarity in IQ of same family

c) An adopted child seems to be more intelligent than the parents

However for the same inferences there can be the following environmental evidence-

a) The generations of the family must have been residing at a rich environment which causes the IQ similarity

a) Sibilings might be possessing similar genetic maps and thus seems  to be one having high IQ

c) An adopted child must have come from a good environment that the environment of his current parent.

All these gave a clear indication that IQ level can be very well explained by both heredity factors as well as the environmental factors an thus this similar explanation causes the confusion (also there is no strong scientific backing )

It ends up hard to separate hard to separate among heredity and condition with regards to knowledge in light of the fact that there have been confirmations.

Explanation:

Hereditical confirmations  The ages of a high IQ individual groups high IQ.  Siblings have abnormal state of similitude in IQ of same family A received tyke is by all accounts more shrewd than the guardians .Anyway for similar surmisings there can be the accompanying natural proof a) The ages of the family probably been dwelling at a rich domain which causes the IQ closeness  a) Sibilings may have comparative hereditary maps and along these lines appears  to be one having high IQ  c) An embraced tyke more likely than not originate from a decent situation that nature of his current parent.  All these gave an unmistakable sign that IQ level can be exceptionally very much clarified by both heredity factors and also the natural factors a hence this comparative clarification causes the disarray

your answer is "the 1950's"

meiosis is the first to occur after the nuclei of opposite of opposite mating types fuse