No, adjective clauses modify nouns. The only things adjectives modify are nouns and pronouns.
Adverb Clause
An adjective modifies a noun or a pronoun. (it can also modify a noun phrase or clause)
It modifies a verb, adjective, or an adverb.
Astronomy
Yes, the relative pronoun "who" begins adjective clauses, those that modify nouns. The same applies to the words whom, whoever, whose, that, and which.
adjective clause
You could modify a phrasal verb (more than one word), or modify an entire clause with an adverb such as "fortunately."
No. It is an adjective clause, as it begins with a relative pronoun (who).
The clause in parentheses, "who wrote Gothic and macabre short stories," is an adjective clause. It provides additional information about the noun "Edgar Allan Poe," describing what kind of author he was. Adjective clauses modify nouns, whereas adverb clauses modify verbs, adjectives, or other adverbs.
An adverb can modify verbs, adjectives and other adverbs.
No, "although the ostrich is a bird" is not an adjective; it is a dependent clause. In this clause, "although" is a subordinating conjunction, "the ostrich" is the subject, and "is a bird" is the predicate. An adjective describes a noun, but this phrase serves to provide a contrast or concession rather than modify a noun.
The clause "who can cook " is basically an adjective clause because it refers to a noun.For example:The pilot who can cook prepared the food for the survivors." who can cook " refers to pilot.*The question is also whether it is a restrictive or non-restrictive clause. If the pilot is the only one of the pilots who can cook, it is a restrictive clause (the one who can). If the pilot just happens to be able to cook, it is a non-restrictive clause set off by commas, e.g.The pilot, who can cook, prepared the food for the survivors.