Some are retained and passed on each generation (Like for brown eyes), or can get "lost" but then pop up again every so often (like red hair in 1st generation but no red hair again till 3rd generation). even if for many generations a certain trait seems "lost" every member still has a chance to get that gene, a carrier you might say.
The six ones that affect our opinions would be newspapers, movies, magazines, propaganda, television, and radio. The only one that doesn't is dictionaries.<span />
