Select the correct text in the passage. Which statements in this passage about volcanoes do not contain factual errors?

The Hawaiian islands are known for their volcanic activities. In fact, the islands were formed from volcanoes. Before a volcano erupts, earthquake activity beneath the volcano decreases. Scientists use seismometers to measure the earthquake activity that occurs beneath a volcano. They then predict the eruption of that volcano. When a volcano erupts, the amount of carbon dioxide and sulfur dioxide emitted decreases. Scientists measure the amount of these gases to determine the amount of magma present in the volcanic reservoir.

(I couldn't find the science subject so I just put chemistry)

The answers are

1. Scientists use seismometers to measure the earthquake activity that occurs beneath a volcano. They then predict the eruption of that volcano.

2. Scientists measure the amount of these gases to determine the amount of magma present in the volcanic reservoir.  

Explanation:

When a volcano is near eruption Earthquake activity gets stronger and stronger. Scientists use a wide variety of techniques to monitor volcanoes, including seismographic detection of the earthquakes and tremor that almost always precede eruptions, precise measurements of ground deformation that often accompanies the rise of magma, changes in volcanic gas emissions, and changes in gravity and.

Scientists can use the FTIR or Fourier Transform Infrared Spectrometer to measure dissolved volatile concentrations as described above or can be used to measure several gases emitted from a volcano simultaneously. The device can be used both as an open-path or closed-path system. I had just taken the test and got the question right as well