Short-sightedness is to a large extent inherited, its incidence varies from one family to another. The reason behind the link between the common incidence of short-sightedness and high intelligence is unclear. Previous generations thought that eyes could become strained by years spent poring over books, but a few decades ago the popular medical view was that short-sighted people gravitated towards the library because they found it hard to excel at sports. Recently there has been partial support for a theory that high intelligence and short-sightedness may, in fact, be part of a genetic package.

Question: Intelligence is to a large extent inherited.
Options:
A. true, B. false, C. uncertain
Answer: "C"