Answer:infectious disease
Explanation:
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Answer is Middle Paleozoic era.
Paleozoic era was in 542 Ma - 245 Ma and it has 6 periods as Cambrian, Ordovician, Silurian, Devonian, Carboniferous and Permian.
360-280 Ma - forming of vascular plants with woody tissues, seeds and veins.
430 - 410 Ma - forming of jawed fishes and first amphibians.
420 Ma - forming of scorpions
360 Ma - forming of crustaceans.
The left atrium lacks a group of pace maker cells.
Organism X existed for a short period of time. I really like geology so trust me, I am 100% sure about this question.
(Mark me as the brainiest if this answer helps you!)
C) Tectonic is not a type of plate boundary