Which sphere does a volcanologist most directly study?

Volcanoes are formed when the magma rises up towards the surface of the earth. It takes place near active plate boundaries as well as in the regions of hotspots. Scientists who study the volcanoes are considered as the volcanologist.

The sphere in which a volcano is directly studied is the lithosphere,

Volcanoes are formed both on the land areas as well as over the ocean floors. And as volcanic eruption takes place, a huge amount of toxic gases are released into the atmosphere. So, a volcano interacts overall with the geosphere, which collectively includes the lithosphere, atmosphere, and the hydrosphere.

before, trains worked using the steam engine. thus, it uses heat so it is crucial to apply heat balance. the steam engine absorbs energy during the stage of boiling water. so, this is the endothermic reaction. when the steam is used to work the piston, it has to release this energy through running the train. the excess energy is released as an exhaust to the chimney. this is the exothermic process because it releases energy to the surroundings.

the answer would be d : p