Two factors which affect water potential are the amount of solutes and external pressure.

Explanation

To answer the question regarding the two factors that affect water potential, we can break down the explanation into a few clear steps:

### Step-by-Step Solution:

1. **Understanding Water Potential**: Water potential (Ψ) is a measure of the potential energy in water and is crucial in understanding how water moves in plants. It is influenced by two main components: solute potential (Ψs) and pressure potential (Ψp).

2. **Formula for Water Potential**: The formula for calculating water potential is:
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