If you know an older …(1)… person, chances are they had to learn to write
or eat with their right hand. And in many parts of the world, it's still common …(2)…to force children to use their "proper" hand. Even the word for right
also means correct or good, not just in English, but many other languages, too. But if being left-handed is so …(3)…, then why does it happen in the first place?
Today, about 1/10 of the world's population are left-handed. Archeological evidence shows that it's been that way for as long as 500,000 years, with about 10% of human remains showing the associated …(4)…in arm length and bone density, and some ancient …(5)…and artifacts showing evidence of left-hand use. And despite what many may think, handedness is not a …(6)…
It can be predicted even before …(7)…based on the fetus' position in the womb. So, if handedness is inborn, does that mean it's genetic? Well, yes and no.
Identical …(8)…, who have the same …(9)…, can have different dominant hands. In fact, this happens as often as it does with any other sibling pair. But the chances of being right or left-handed are determined by the handedness of your …(10)…in surprisingly consistent ratios.
>>Làm tiếp phần 2
>>Xem đáp án phần 1
archeological: khảo cổ học
handedness: khuynh hướng chỉ dùng một tay
fetus: thai nhi
womb: bụng mẹ
inborn: bẩm sinh
genetic: di truyền
dominant hands: tay thuận