Yes it is both.
Mitochondria is already plural. The singular form is Mitochondrion.Mitochondria IS plural. The single form is mitochondrion.
The word mitochondria is the plural form; the singular noun is mitochondrion.
Mitochondria is the plural word.Mitochondrion is singular form.
That it is. But mitochondria is the plural. Mitochondrion is the singular.
The mitochondrion (singular), mitochondria (plural).
It is both a singular or plural noun.
Fish is both singular and plural.
Fish is both singular and plural.
Epidermis is both singular and plural
Both singular and plural.
The verb reviewed is used after both singular and plural nouns.
Yes, "sheep" can be used as both the singular and plural form.