Critical periods after birth exist for
learning languages
correcting present birth defects
going through withdrawals
sparrows finding their mates

The correct answer is learning languages

It is common to divide the early stage of language acquisition into two phases: pre-linguistic and linguistic. At the pre-linguistic stage, the child's language ability develops without any identifiable language production.

The babbling stage is marked by a variety of sounds that are often used in any of the world's languages, though often not the language the child will later speak. The meaning of this observation is unclear. Some claim that babbling signals the beginning of a child's language communication skills.

answer; the federal reserve system;

could you go a bit more in depth with you question? it's quite hard to understand. as soon as you do that i will be glad to : )