3. Tigers and goldfish are not related.
Tigers and goldfish ARE related.
Even though they are not closely related, they are both vertebrae animals, and they also share the same Phylum. Though they are in different classes (Tigers belong to the Class Mammalia, while Goldfish belong in the Class Actinopterygii), BUT they both belong to the Phylum Chordata.
5. Mammals and plants don't belong in the same domain.
Mammals and plants DO belong in the same domain.
Mammals and plants belong in the same domain called Eukarya. However, Eukarya is divided into four kingdoms: Fungi, Plantae, Animalia, and Protista.