38. when erosion wears away the outside of a volcano, sometimes a solid magma core called a is left exposed.
a. cinder cone
b. volcanic neck

volcanic neck

Explanation:

volcanic neck

the volcanic neck which is also known as the volcanic plug is a type of land form of the volcano which formed when lava from volcano hardened inside the vent of an active volcano. Due to hardened magma intense pressure is build up which sometimes become the cause of explosion in volcano

within these regions are all the major types of biomes in the world. a biome is a community of animals and plants spreading over an extensive area with a relatively uniform climate. some diverse biomes represented in north america include desert, grassland, tundra, and coral reefs.