Which element is found in all living cells on Earth?

• A. Iron (Fe)
• B. Sodium (Na)
• C. Chlorine (Cl)
• D. Carbon (C)

Answer: (D)

Verified step by step guidance

1. Step 1: Understand the context of the question. The problem is asking which element is universally found in all living cells on Earth. This requires knowledge of the basic building blocks of life.
2. Step 2: Recall that living organisms are primarily composed of organic molecules, which are molecules containing carbon. Carbon is the backbone of these molecules, such as carbohydrates, lipids, proteins, and nucleic acids.
3. Step 3: Compare the options provided: Iron (Fe), Sodium (Na), Chlorine (Cl), and Carbon (C). While Iron, Sodium, and Chlorine are important for specific biological functions, they are not universally present in all living cells.
4. Step 4: Recognize that Carbon (C) is unique because it forms the basis of organic chemistry and is essential for the structure and function of all living cells.
5. Step 5: Conclude that Carbon (C) is the correct answer, as it is the fundamental element found in all living cells on Earth.