The correct answer to 19) is A: to inform.
The purpose of this article is to inform, that is, to explain and tell someone about particular facts; in this particular case, the authors informs about the discovery of a new unnamed island in the northern Pacific Ocean. This article seek to explain how volcanoes are formed and how important or relevant these volcanoes are to Earth.
The other options are not possible answers since the article does not include specific vocabulary or literary techniques that may influence the readers or make them think in a particular way. Moreover, the article is not written to entertain the readers since it only presents factual information for those who are interested in these kind of topics or who want to learn about this new discovery.
The correct answer to 20) is A: the author's purpose is to inform the reader about how a new Pacific island was formed.
As explained above, the author wants to share with the audience the discovery of a new unnamed island in the Pacific Ocean. The author presents explicit information about the island, such as location and dimension, and then he/she provides factual details about how volcanoes are formed and how these eruptions affect the Earth's surface and plates.
For this reason, the other options are not possible. The author does not present jokes nor expressions to make the readers laugh. Moreover, the author does not explain the uses people can make on this island and he does not describe the flora and fauna (plants and animals) that may live on this island.
