Answer:
Many scientists favor the RNA world hypothesis, in which RNA, not DNA, was the first genetic molecule of life on Earth. Other ideas include the pre-RNA world hypothesis and the metabolism-first hypothesis. Organic compounds could have been delivered to early Earth by meteorites and other celestial objects
They are different in structure as one serves in an open system (lymphatic system) while the other serves is closed system (circulatory system).
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*This question is common, so this answer I use a lot. I copied my own work.*
The answers A. C. D. are all physical reactions
The answer is B. Digestion of food
When food is digested it is chemically broken down
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