Answer:
landslide
This is so easy you can answer this if you study and cheat on class
Explanation:
In the majority of cases, the extra copy of chromosome 21 comes from the mother in the egg.
In a small percentage (less than 5%) of cases, the extra copy of chromosome 21 comes from the father through the sperm.
In the remaining cases, the error occurs after fertilization, as the embryo grows.
Answer:
The answer is 3. Double Helix.
A. punnet square The punnet square is used to help determine genetic things using the parents as a guide like the color of a rose if something will be tall or short hope you ask more Qs like this i # luv science. heheheheheh hahahahahaha
