What is a reasonable explanation for why some genes still remain in the mitochondria?

Why do scientists believe that mitochondria evolved before chloroplasts? A. because all eukaryotic cells have mitochondria but not all eukaryotic cells have chloroplasts B. because mitochondria are more efficient than chloroplasts C. because mitochondria live longer than chloroplasts D. because mitochondria are larger and stronger than chloroplasts Chrome OS Wien

Domestic dogs are closely related to wolves. Wolves have one copy of the gene that encodes the enzyme amylase. Amylase is required to digest starch. Dogs have between 4 and 30 copies of this gene. Explain how the new copies arose in the genome of the domestic dog. Compare this to the evolution of lactase persistence in humans. Explain how the diet and environment of a dog compared to a wolf would result in fixation of the duplicated gene. What possible explanation is there for the variation of copy number among dog breeds?

Which of the following observations would support the Darwinian theory for the evolution of cancer cells (select all that apply)?   A. Mutations enable tumor cells to grow faster than normal cells.   B. Cells within the tumor each have different mutation in RAS   C. Cells isolated from a tumor are all found to have an inactivating mutation in a gene that is normally pro-apoptotic   D. Cells of the same type isolated from a tumor are all found to have multiple identical mutations   E. Cells of the same type isolated from a tumor are found to be genetically distinct and have different types of mutations