Q? evolution of life on a different Earth-like planet
On a hypothetical Earth-like planet (similar temperatures, liquid H2O, atmosphere, magnetosphere, land mass etc.) is there any reason to think that multicellular life might develop similarly to what we see on Earth? Such as organisms that have chitin, cartilage, bone and muscle, even if the chemistry is different? Not organisms that look like Earth organisms, but something similar to vertebrates with appendages?
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Bonus question, is panspermia considered some old, obsolete notion these days or is there anyone who considers it plausible?