Which of the following MUSt exist in population before natural selection can act upon that population? genetic variation among individuals B) variation among individuals caused by environmental factors sexual reproduction D)A and € only E)A. B and € What characteristic would all protobionts have had in common? A) the ability synthesize enzymes B) surounding membrane Or membrane-like structure C) RNA genes D) nucleus E) the ability to replicate RNA 10. What is the correct sequence of these events_ from earliest to most recent; in the evolution of life on Earth? origin of mitochondria origin of multicellular eukaryotes origin of chloroplasts origin of cyanobacteria origin of fungal-plant symbioses A) 4 3.2.1.5 B) 4 1. 2.3.5 C) 4 1,3.2.5 D) 4 3. 1.5. 2 E) 3.4 1.2. 5