No, it is not. Sources can be a plural noun, and more rarely a verb form from the nonstandard verb to source.
There is no adjective form of 'mystify.' However there is an adverb form. See Sources and Related Links.,
There are no adverbs.The word many is an adjective (number of nutrients). The word plant could be considered an adjective for the noun food, but is more strictly a noun adjunct that makes "plant sources" the subject.
It might be, but sources disagree. It is either an adjective or a noun adjunct when used in terms such as garlic powder, garlic butter, and garlic toast.
No, it is more correctly referred to as a possessive adjective (precedes nouns).The possessive pronoun is "your" (some sources refer to 'your' as an absolute possessive pronoun because it can stand alone).
No. Likable or likeable is an adjective. Only some sources recognize the adverb "likeably" (likably).
The word expressly is an adjective. EX: He expressly rejected the proposal. Sources: Webster dictionary
Not in modern usage. Plenty is usually a noun, and usually refers to an unspecified number, quantity, or value (plenty of people, plenty of time, plenty of food). *some sources classify "plenty" as a quantifier rather than a noun or adjective *historically the term "plenty" was also used to mean plentiful, which is an adjective
The word "late" can function as both an adjective and an adverb. As an adjective, it describes something or someone that is not on time or arriving after the expected time. As an adverb, it describes an action or event that occurs after the expected or usual time.
The word "a" is called an indefinite article, an adjective that means one unspecified example, object, or person of a given group, e.g. a subject, a toy, a man. *most sources classify a, an, and the (the three articles) as determiners rather than adjectives.
Comp is the abbreviation. Comprehensive is an adjective that means all or nearly all elements or aspects of something are included. For example, you could have a comprehensive list of sources.
Nouns: vacation, statesverb: droveAdjective: summerAdverb: through*Note: the word twelve is often called a determiner when used in combination with the noun states, but other sources consider it an adjective.
No, it is a verb or a noun (to go around, to surround; a round shape). The adjective form is circular.