The constituents of atomic nuclei are believed to be

Options

A. neutrons and protons
B. protons only
C. electrons and protons
D. electrons, protons and neutrons

Answer

To solve the question regarding the constituents of atomic nuclei, we can follow these steps:

### Step 1: Understand the Structure of an Atom
An atom consists of a nucleus at its center, which contains protons and neutrons. Surrounding the nucleus are electrons that revolve in orbits.

### Step 2: Identify the Constituents of the Nucleus
The nucleus is primarily made up of two types of particles:
- **Protons**: These are positively charged particles.
- **Neutrons**: These are neutral particles (no charge).

### Step 3: Analyze the Options Given
The question provides four options, and we need to determine which one correctly identifies the constituents of atomic nuclei.

### Step 4: Confirm the Correct Answer
Since we have established that the nucleus is made up of protons and neutrons, we can conclude that the correct answer is:
- **Protons and Neutrons**.

### Final Answer
The constituents of atomic nuclei are believed to be **protons and neutrons**.

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