It is now believed that protons and neutrons (which constitute nuclei of ordinary matter) are themselves built out of more elementary units called quarks. A proton and a neutron consist of three quarks each. Two types of quarks , the so called 'up' quark, (denoted by U) of charge `+ (2//3)` e and the 'down' quark (denoted by d) of charge `(-1//3)` e together with electrons build up ordinary matter. (Quarks of each other types have also been found which give rise to different unusual varieties of matter). Suggest a possible quark composition of a proton and neutron.

Explanation

To determine the quark composition of a proton and a neutron, we need to understand the charges of the quarks involved.

### Step-by-Step Solution:

1. **Identify the Charges of Quarks**:
- Up quark (U) has a charge of \( +\frac{2}{3} e \).
- Down quark (d) has a charge of \( -\frac{1}{3} e \).

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