Volcanoes that have erupted before and still show signs of possible eruption again are said to be

Step 1: Analyze the question The question asks for the term used for a volcano that has erupted in the past and still shows signs that it could erupt again.

Step 2: Explain the concept Volcanoes are classified by their level of activity:

• Active: Erupting now or erupting regularly (e.g., Mount Etna).
• Dormant: "Sleeping." It has erupted in recorded history and is currently quiet, but it still shows signs of life (gas emissions, minor tremors, hot springs) and may erupt again.
• Extinct: It is not expected to erupt again. There is no magma supply and no signs of activity (e.g., Mount Kenya).

"Weak" and "ongoing" are not standard volcano classifications.

Step 3: Apply to the options

• A. Weak: not a classification of volcanoes.
• B. Ongoing: this would describe a volcano erupting right now, not one that has erupted before and is currently quiet.
• C. Dormant: it fits, because the volcano has erupted before and could still erupt again.
• D. Extinct: this contradicts "still show signs of possible eruption."

Step 4: Answer The correct option is C. dormant.

Exam tip: Think of "dormant" as "dorm" (sleep). A dormant volcano is asleep but can wake up. An extinct volcano is "dead" and will not wake up.