In genetics, gene expression is the most fundamental level at which the genotype gives rise to the phenotype, i.e. observable trait. ... Such phenotypes are often expressed by the synthesis of proteins that control the organism's structure and development, or that act as enzymes catalyzing specific metabolic pathways.
Answer:
Reptiles
Explanation:
Vertebrate paleontology covers everything from the tiny, fish-like creatures, to the salamander-like ancestors of all land vertebrates, to dinosaurs, mammals, flying and swimming reptiles, etc.
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