No, ‘also’ is not a preposition. It is classified as an adverb.
Adverbs are words that modify verbs, adjectives, or other adverbs. In the case of ‘also’, it is used to indicate addition or agreement, meaning ‘in addition’ or ‘as well’. For example, in the sentence ‘She speaks French and she also speaks Spanish,’ ‘also’ adds information about the second language she speaks.
Prepositions, on the other hand, are words like ‘in’, ‘on’, ‘at’, and ‘by’ that show relationships between nouns or pronouns and other words in a sentence. Since ‘also’ does not fit this description and serves a different function in a sentence, it is correctly identified as an adverb.