OTHER 发表于 2025-3-28 17:15:24
Population Distribution,st gnathostomes were marine fishes with the head and thorax generally covered with bony plates. They flourished in the Devonian and became extinct in the Carboniferous. The Gnathostomata thus includes almost all the living vertebrates which are divided into the six classes: Chondrichthyes, Osteichthfollicular-unit 发表于 2025-3-28 22:05:00
Population, Food, and the Environment,gh the evolution of the cleidoic (closed box) egg. Such an egg is large and has a tough leathery or calcareous shell. The shell protects the developing embryo from mechanical damage and, being porous, permits the entry of air for respiration and, at the same time, impedes loss of water by evaporatiobacteria 发表于 2025-3-29 00:33:37
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