This is an example of vestigial structure.
Vestigial structures are structures (cells, tissues and organs) found in an organism that has lost most or all of its primitive function through evolution. The vestigial structure has performed vital functions in the organism in the past but as there are changes in species as a result of natural selection, the structure became less important until it no longer functions. A reduced nonfunctional digit on the paws of dogs known as a dewclaw is an example of vestigial structure.
An organelle that releases energy through a common biological process that is common to eukaryotes is the mitochondrion, this would be cellular respiration.
I can't see the letters that much? The pic is blurry for me sorry.
