What do you mean by (+) and (0) relationship ?

Explanation

### Step-by-Step Solution:

1. **Definition of Positive and Zero Relationship**:
- The positive and zero relationship refers to a type of interaction between two different species where one species benefits while the other remains unaffected.

2. **Understanding the Terms**:
- The term "positive" indicates that one species gains an advantage or benefit from the interaction.
- The term "zero" signifies that the other species does not experience any benefit or harm; it remains neutral in the interaction.
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