D. 1,200
This is because if it takes 1 and a half hours **1.5** to travel through city a and city b , and the plane goes 800km per hour and 400km is half of that it then the answer has to be d.
The three-dimensional compositions have more silicon in comparison to those composed of independent tetrahedra.
The silicate minerals refer to the most general of Earth's minerals and involve feldspar, quartz, mica, pyroxene, amphibole, and olivine. On the other hand, the silica tetrahedra composed of oxygen and silicon, produce sheets, chains, and frameworks, and bonds with other cations to produce silicate minerals.
Answer:


What is carbon hydro

<h3><u>A hydrocarbon is a molecule whose structure includes only hydrogen and carbon atoms</u></h3>
Explanation:
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<em>The carbon atoms join together to form the framework of the compound, and the hydrogen atoms attach to them in many different configurations.</em></u></h3><h3><u>
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