10. a(n) sequence can be compared between two different organisms to determine their relationship. 11. a structure that had a function in the past like the wings of an ostrich but do not have a function now are called

The answer to the 1st question is a DNA base sequence.  This is done through observing amino acid sequence, the more recent the common ancestor is, the more closely related the species are.

The answer to the 2nd question is vestigial.  The wings of the ostrich became functionless in the course of evolution. The wings atrophied that it can no longer be used for flying.