One athlete, many athletes. The collective word is "team".
The word 'athlete' is a noun, a word for a person.
The plural of wolf is wolves.
The singular possessive is athlete's. The plural possessive is athletes'.
Weapons is the correct plural for the singular noun weapon
Careers is the plural of career.
No, if you are referring to the plural of "goose" the correct plural noun is "geese".
The plural of the word "subject" is "subjects".
The correct plural form of "foot" is "feet."
While a dictionary will tell you that the plural is either "maxima" or "maximums", only "maxima" is the correct plural in the original Latin (that is in spite of my spell checker not knowing that word and allowing "maximums" as correct).
Cyclopes
rainfalls
That is the correct spelling of the word "sky" (plural skies).