(Q014) Silicates a. are classified on the basis of what kind of metals they contain. b. form through the evaporation of water. c. are a large category of minerals that includes the common minerals calcite and dolomite. d. have the silicon-oxygen tetrahedron as their structural unit.

d. have the silicon-oxygen tetrahedron as their structural unit.

Explanation:

Silicates are anions that have both Oxygen and Silicon as the basis of their structure. These two form a tetrahedron type structure that enable them to be useful for a whole lot of things.

Silicates are very abundant on Earth as they comprise around 95% of the Earth's crust as well as the upper mantle which explains why they are mostly found in igneous rocks.

its first and third is your answer i did the qustion the fourth isnt right