Answer:
The chance of a normal couple having a child with down syndrome is 1 to 600 births.
Explanation:
Down syndrome is a genetic flaw that occurs when the fetus is being formed.
A human cell considered normal has 46 chromosomes, divided into 23 pairs. For some unknown reason, an error may occur at the beginning of embryonic development and an extra chromosome is created, which binds to par 21. The result is cells with 47 chromosomes. This causes the said syndrome.
It is important to know that this failure happens at random. It is nobody's responsibility. It has not been proven to date that lifestyle, actions during pregnancy, smoking, drinking, medicines, environmental factors or kinship between the couple can influence this occurrence. She is not contagious either. The likelihood of a normal couple having a child with the syndrome is approximately 1 to 600 births.
To show the different levels of classification and divide among species, and different organisms on planet Earth. It also creates a universal "language" for scientists around the world when referring to organisms (cougar & puma are the same animals; different name)
Example: The American Alligator and the Chinese Alligator (look it up!) are in the same family and genus, but are not the same species.
i think c. is the best answer , we just got off that topic like a week ago .