Argument need not be optional to have a default value defined

Author: gpj1

src/pages/learn/schema.mdx

@@ -63,7 +63,7 @@ type Starship {
 
 All arguments are named. Unlike languages like JavaScript and Python where functions take a list of ordered arguments, all arguments in GraphQL are passed by name specifically. In this case, the `length` field has one defined argument, `unit`.
 
-Arguments can be either required or optional. When an argument is optional, we can define a _default value_ - if the `unit` argument is not passed, it will be set to `METER` by default.
+Arguments can be either required or optional. We can define a _default value_ for an argument as well - if the `unit` argument is not passed, it will be set to `METER` by default.
 
 ## The Query and Mutation types