Which of these is considered as the fundamental unit of matter?

Options

A. Atom
B. Protons will flow from the positively-charged objects towards the negatively-charged object.
C. Neutron
D. Electrons and protons

Answer

To answer the question "Which of these is considered as the fundamental unit of matter?", we can follow these steps:

### Step-by-Step Solution:

1. **Understanding Matter**:
- Matter is defined as anything that occupies space and has mass. This includes solids, liquids, and gases.

2. **Identifying the Options**:
- The options given are:
A) Atom
B) Proton
C) Neutron
D) Electron

3. **Defining the Fundamental Unit of Matter**:
- The fundamental unit of matter is the smallest unit that retains the properties of an element. This is known as an atom.

4. **Analyzing the Options**:
- **Proton**: A proton is a subatomic particle found in the nucleus of an atom. It is not a fundamental unit of matter but a component of an atom.
- **Neutron**: Similar to protons, neutrons are also subatomic particles found in the nucleus of an atom and are not considered a fundamental unit of matter.
- **Electron**: Electrons are negatively charged subatomic particles that orbit the nucleus of an atom. They are also not the fundamental unit of matter.

5. **Conclusion**:
- Among the options, the atom is the only one that is considered the fundamental unit of matter. Therefore, the correct answer is **A) Atom**.

### Final Answer:
The fundamental unit of matter is **A) Atom**.