Occasionally a child is born with an extra chromosome 13, but never do you see a child with an extra chromosome 12, why?

This is because some of the trisomies (one extra chromosome, three instead of two) are fatal, births cannot survive.

Theoretically, trisomies can occur with any chromosome, but often result in miscarriage.

The types of autosomal trisomy that survive to birth in humans are:

Trisomy 8 or Warkany syndrome 2

Trisomy 9

Trisomy 13 or Patau syndrome

Trisomy 18 or Edwards syndrom

Trisomy 21 or Down syndrome.

velocity and height

sulfur dioxide

explanation: acid rain is caused by a chemical reaction that begins when compounds like sulfur dioxide and nitrogen oxides are released into the air. these substances can rise very high into the atmosphere, where they mix and react with water, oxygen, and other chemicals to form more acidic pollutants, known as acid rain.