What can scientist use to predict volcanic eruptions? select all that apply

determining if the volcano is active or not
monitoring earthquakes, ground swelling, and water indicators
tracking surface temperatures of crater
increase in sulfur dioxide emissions

(Determining if the volcano is active or not.)    (Monitoring earthquakes, ground swelling, and water indicators)  (Increase in sulfur dioxide emissions)

The answer is:

Determining if the volcano is active or not - A volcano is deemed active if it is currently erupting or shows signs of erupting in the near future. Monitoring earthquakes, ground swelling, and water indicators - Moving magma move the ground, so the amount and intensity of earthquakes rise before an eruption. A volcano that will erupt soon may produce a chain of earthquakes. Magma and gas can drive the volcano’s slope upward and ground swelling produce huge changes in the shape of a volcano.Increase in sulfur dioxide emissions- Gases leave a volcano before magma reaches the surface. Scientists measure gas emissions in vents on or around the volcano. Gases, such as sulfur dioxide, carbon dioxide, and even water vapor can be measured locally or, in sometimes, from space using satellites. The number of gases and their proportions are determined to help predict eruptions.

I'm pretty sure it's c. extremely gradual but not 100% sure though.

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