The Heritability of Intelligence Among Older People Is _____ Than

The heritability of intelligence among older people is _____ than the heritability among young people, perhaps because _____.

A) higher; older people have more similar experiences than younger people
B) higher; intelligence levels have slowly been decreasing over the decades
C) lower; access to education has improved over the years
D) lower; the average diet is more nutritious now than it was in the past