The president of the united states is preparing his state of the union message. in the sentence, which part of speech is the word his? demonstrative adjective possessive adjective compound adjective indefinite article

The details about the statues, i believe, are that they're carved from blocks of igneous stone, many of them are partially buried under the ground which to preserve and protect them from the harsh environment on easter island, and many of the facial features have washed away. also, the most well-preserved one is at the british museum in london.these are just guesses from what i can see and what i think i read correctly. i'm sorry i couldn't be more .