.I have found the following used but have been confused about why countable nouns at some times and uncountable nouns at other times.
Different groups have called for the recognition of their cultures.
Different groups have called for the recognition of their culture.
Without context, the former could mean that the groups have differing cultures, and the second could mean different groups who all subscribe to one culture.
The country has been gripped by political crisis.
the country has been gripped by a political crisis.
This is essentially the same. The former is a general reference [some kind of political crisis], the second is a specific reference [a particular political crisis].
The plural for crisis is crises.