The plural form of the noun country is countries.
The plural possessive form is countries'.
Example: All of the countries' representatives have been seated.
The word countries is the plural form of the singular noun country.The possessive form of the plural noun is countries'.The singular possessive form is country's.
The plural possessive form is countries'.Example: All of the countries' delegates had to agree to the plan.
The plural form for the noun country is countries.The plural possessive is countries'.Example: The success was the result of many countries' cooperation.
The plural form of the noun country is countries.The plural possessive form is countries'.Example: All of the countries' representatives have arrived.
The possessive form of the singular noun country is country's.The plural form of the noun country is countries.The plural possessive form is countries'.Examples:The country's income is derived mainly from tourism.All of the countries' representatives were in attendance as the meeting began.
The plural form for the noun country is countries.The plural possessive is countries'.Example: The success was the result of many countries' cooperation.
The plural form of the noun country is countries.The plural possessive form is countries'.Example: All of the countries' representatives have been seated.
The possessive form of the plural noun countries is countries'.Example: All of the countries' delegates had to agree to the plan.
The possessive form for the plural noun countries is countries' (just as you have it in your question).Example: All of the countries' flags surrounded the field.
The singular form for the plural noun countries is country; the singular possessive form is country's.
The plural form for the noun buzz is buzzes; the plural possessive form is buzzes'.
The plural form for the noun tree is trees.The plural possessive form is trees'.