Which of the following produce a quiet volcanic eruption?
a) magma that is rich in silica
b) magma that is fluid
c) magma that is low in iron
d) magma that is low in silica.

D magma that is low in silica. A low silica content means there are fewer bonds resulting in a much more viscous lava. For example, the constant eruptions common in Hawaii are very quiet because the lava is viscous meaning it does not require a lot of energy to erupt. High silica content usually results in much more pressure such as at Mount St. Helens. These eruptions are very loud because of the pressure necessary to break the silica bonds.

The answer is a but it also might be 7 so

Tropical climate is experienced in the nothern countries of south america