Answer: That depends.
Some words look like plurals, but are actually singular. In addition, some mass nouns and abstract nouns can go either way.
Take for example the word “water.” It is a mass noun like “flour” or “rice,” and is normally singular. However, I’m sure you have heard about how drillships are used in ultradeep waters (plural), indicating various places around the world. Likewise, mass nouns like “beer” and “wine” become plural when differentiating between the various kinds.
Beers and wines take on different flavors depending on the waters used in their fermentation.
Then there are the abstract nouns, such as Physics, Geophysics, and Politics. These represent a mass of thought, as it were, and normally take a singular verb.
Geophysics is the study of physical processes and phenomena occurring in the earth.
However, in some constructions, “geophysics” can be plural:
The interpretation is subject to change, depending on what the actual geophysics are.
I saw a headline in the newspaper the other day that showed how even professional journalists can err in their decision as to whether an abstract noun is singular or plural.
All Politics Is Local
Yes, “politics” can be singular:
Politics is a topic that should be forbidden at our family gatherings.
But when you talk about all politics, obviously you are referring to more than one, so the noun should take the plural verb in that case.
All Politics Are Local