I have two questions.
(1) I know that we should say "Dogs are a type of animal". I wonder why we don't say "Dogs are a type of an animal"? For some reason, we have no article before animal. Is that just idiomatic?
(2) I'm confused as to when a noun is countable or not. For example, if you read the beginning of this Wikipedia page:
Equality of outcome, equality of condition, or equality of results is a political concept which is central to some political ideologies and is used regularly in political discourse, often in contrast to the term equality of opportunity.
I know that outcome could be a countable noun. For example, we say "these are two different outcomes." However, equality of outcome treats outcome as an uncountable noun (or a mass noun). Why can't we say, then, "equality of result"? "Outcomes" and "results" are essentially the same thing, right?