It's sheep; same as for one of them.
The plural way to spell studio is studios.
The plural of activity is activities.
The plural possessive for the noun dish is dishes'.
The plural form of Cameron is Camerons.
languages
Halos is the correct way to spell the plural form.
geese
cockroach (plural cockroaches.)
Just that way.
The plural of ostrich is ostriches.
"pen", the sheep were in their pen. a pen is what you could put sheep in.
The plural possessive form for comity (one m) is comities'. If you meant the noun committee, the plural possessive form is committees'. If you meant the noun community, the plural possessive form is communities'.