mammal is a kind of taxonomic group of animals & fur is usually part of a mammal ->  animals in the taxonomic group mammal usually have fur  a fish does not have fur & fish is a kind of taxonomic group of animals ->  animals in the taxonomic group fish do not have fur  a bird does not have fur0 & amphibian is a kind of taxonomic group of animals ->  animals in the taxonomic group amphibian do not have fur  animals in the taxonomic group fish do not have fur & animals in the taxonomic group amphibian do not have fur ->  animals in the taxonomic groups fish and amphibian do not have fur  a bird does not have fur & bird is a kind of taxonomic group of animals ->  animals in the taxonomic group bird do not have fur  a reptile does not have fur & reptile is a kind of taxonimic group of animals ->  animals in the taxonomic group reptile do not have fur  animals in the taxonomic group bird do not have fur & animals in the taxonomic group reptile do not have fur ->  animals in the taxonomic groups bird and reptile do not have fur  animals in the taxonomic groups fish and amphibian do not have fur & animals in the taxonomic groups bird and reptile do not have fur ->  animals in the taxonomic groups fish and amphibian and bird and reptile do not have fur  animals in the taxonomic group mammal usually have fur & animals in the taxonomic groups fish and amphibian and bird and reptile do not have fur ->  fur is only part of animals in the taxonomic group mammals  fur is only part of animals in the taxonomic group mammals -> fur is only part of animals of one taxonomic group