The most abundant element in the universe is thought to be

Options

A. carbon
B. oxygen
C. hydrogen
D. nitrogen

Explanation

To determine the most abundant element in the universe, we can follow these steps:

### Step 1: Understand the context of the question
The question asks for the most abundant element in the universe, which requires knowledge of the composition of the universe.

**Hint:** Think about the elements that are commonly found in stars and galaxies.

### Step 2: Review the options provided
The options given are:
- A) Carbon
- B) Oxygen
- C) Hydrogen
- D) Nitrogen

**Hint:** Consider the atomic numbers and group classifications of these elements as they may provide insights into their abundance.

### Step 3: Analyze each option
- **Carbon (A)**: Atomic number 6, found in many organic compounds, but not the most abundant in the universe.
- **Oxygen (B)**: Atomic number 8, important for life, but still not the most abundant.
- **Hydrogen (C)**: Atomic number 1, the simplest and lightest element, and is known to be the most abundant element in the universe.
- **Nitrogen (D)**: Atomic number 7, important for biological molecules, but less abundant than hydrogen.

**Hint:** Recall the formation of stars and the processes that occur in stellar environments.

### Step 4: Confirm the most abundant element
Based on scientific understanding and studies of the universe, hydrogen is known to make up about 73% of the visible universe's elemental composition, followed by helium at about 25%. Other elements, including carbon and oxygen, are present in much smaller amounts.

**Hint:** Think about the Big Bang and how elements were formed in the early universe.

### Step 5: Conclusion
The most abundant element in the universe is hydrogen, making option C the correct answer.

**Final Answer:** C) Hydrogen