Chromosomal mutations can have a variety of effects on individuals. down syndrome is a disorder that causes problems such as mild to moderate mental retar and slow or stunted development. a common form of this disorder is the result of a genetic mutation that occurs when there is an extra chromosome 21.

the trilobite is used as an index fossil for various geologic time periods as specific types of the trilobites were present in different geological time periods. they are a group of marine arthropods belonging to the class of trilobita.

explanation:

yes? sounds right, but you didn’t ask a question.

the scientific method.