he heritability of intelligence refers to:

Question 10 options:
the extent to which an individual's intelligence is attributable to genetic factors.
the percentage of variation in intelligence within a group that is attributable to genetic factors.
the extent to which a group's intelligence is attributable to genetic factors.
a general underlying intelligence factor that is measured by every task on an intelligence test.
all of the above are true

Probably all of those are true.

The heritability of intelligence refers to the extent to which an individual's intelligence is attributable to genetic factors. It is generally measured by estimating the percentage of variation in intelligence within a group that can be attributed to genetic factors. So, the correct answer is option 2: the percentage of variation in intelligence within a group that is attributable to genetic factors.