Which statement describes the relationship between plants, animals, and the carbon cycle? Plants use carbon and release oxygen, and animals release carbon and use oxygen.
Animals fix carbon and release oxygen, and plants release carbon and use oxygen.
Animals fix carbon through respiration, and plants fix carbon through photosynthesis.
Plants use carbon when they decompose, and animals release carbon when they decompose.

Part a - which gene to compare? in this exercise, you will use the cytochrome c oxidase i (coi) gene to investigate relationships among salmon species. (this gene encodes a protein that functions in the mitochondrial electron transport chain.) you will compare the coi gene sequences from your salmon test samples to the standard sequences for each salmon species. in order for the coi gene to be useful for distinguishing among the different salmon species, which three statements must be true?