The discovery of the mitochondrial dna (mtdna) has no effect on which area of scientific investigation

The answer is study of cork bark.

According to the process of elimination:

- The endosymbiotic theory explains that mitochondria and chloroplasts descended from the same type of bacteria - thus, mtDNA is important in investigation of endosymbiotic theory

- DNA present in mitochondria is important also for inheritance research and forensic science.

This leaves study of cork bark as the right choice, which is confirmed by knowing that mtDNA contains genes for some metabolic processes.

The answer is study of cork bark.

Explanation:

oxygen is the first element in group 16 (via) of the periodic table. the periodic table is a chart that shows how chemical elements are related to each other. the elements in group 16 are said to belong to the chalcogen family. other elements in this group include  sulfur, selenium, tellurium,  and  polonium.  the name chalcogen comes from the greek word  chalkos,  meaning "ore." the first two members of the family, oxygen and sulfur, are found in most ores.

oxygen is by far the most abundant element in the earth's crust. nearly half of all the atoms in the earth are oxygen atoms. oxygen also makes up about one-fifth of the earth's atmosphere. nearly 90 percent of the weight of the oceans is due to oxygen. in addition, oxygen is thought to be the third most abundant element in the universe and in the solar system.

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