Which of the following elements is the most abundant in the Earth's crust?

• A. Aluminum
• B. Silicon
• C. Oxygen
• D. Iron

Answer: (C)

Verified step by step guidance

1. Understand that the Earth's crust is composed of various elements, but some are more abundant than others based on geological studies and chemical analysis.
2. Recall that oxygen is a major component of many minerals in the crust, often combined with other elements to form oxides and silicates.
3. Recognize that silicon is the second most abundant element in the crust, primarily found in silicate minerals.
4. Note that aluminum and iron are also common but are less abundant compared to oxygen and silicon.
5. Conclude that oxygen is the most abundant element in the Earth's crust because it forms the majority of the crust's mineral compounds.