The answer is ..b .the smallest units of an element ...
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The mitochondria isn't considered to be part of the endomembrane system because its structure is not derived from the nuclear envelope, ER, GolgiApparatus, or cell membrane.
Phase 1: Starts with the separation between populations. Separated populations become adapted to local conditions and become genetically differentiated over time.
Phase 2: Genetic isolation is completed, reproductive isolation develops mostly in the forms of prezygotic RIMs.
They get outta hand and organize
