Species may be singular or plural.
The singular and plural forms are spelled the same.
The word is just spelled species whether singular or plural.
The word species is the singular and the plural form; a species of fish, many species of fish.
The word "specie" means coined (precious metal) money. The word "species" (singular or plural) is a scientific classification (taxon) of living organisms.
The word team is singular; the plural form is teams.
These is plural, this is singular
Lance is singular. Lances is plural.
The word 'Phenomenon' is singular. The plural form is 'Phenomena'.
The word swine is both singular and plural. Just like deer, elk, moose, species, offspring, and many other words.
The word metastasis is singular, metastases is plural.
The word "ground" can be both singular and plural. Singular: "The ground is wet." Plural: "The grounds of the park are well-maintained."
Louse is singular. The plural form is lice.