As every medical student comes to learn when first dissecting the human body at medical school, our limbs are almost entirely composed of muscles.
Being terrestrial is one obvious requirement. No fully aquatic species could master fire and thus develop metallurgy.
Without lignin, there would be no woody plants, no wood, no coal, no charcoal, no fire, no pottery, and certainly no iron or metallurgy.
There is another aspect of the Earth’s environment that is absolutely crucial in allowing the utilization of fire for metal-based technologies.
All these elements of fitness in nature for the development of technology, crucial to mankind’s rise to civilization, long preceded man’s arrival on Earth.