In the equation of the species - area relationship , the letter 'C' and 'Z' represent:

Options

A. C = Regression coefficient , Z = Y - intercept
B. C = Slope of the line, Z = Regression coefficient
C. C = Y - intercept , Z = Slope of the line (regression coefficient)
D. Both (B) and (C)

Answer

To solve the question regarding the species-area relationship and the meanings of the letters 'C' and 'Z' in the equation, we can break it down into clear steps:

### Step-by-Step Solution:

1. **Understanding the Species-Area Relationship**:
- The species-area relationship is a concept that describes how the number of species (species richness) increases with the area being studied. This relationship was notably discussed by Alexander von Humboldt.

2. **The Equation**:
- The equation representing the species-area relationship is given as:
\[ \log S = \log C + Z \log A \]
- Here, \( S \) represents species richness, \( A \) represents the area, \( C \) is a constant, and \( Z \) is a coefficient.

3. **Identifying 'C'**:
- In the equation, \( C \) is the y-intercept when the equation is plotted on a logarithmic scale. This means that when the area \( A \) is equal to 1, the value of \( S \) (species richness) is equal to \( C \). Thus, \( C \) represents the baseline level of species richness.

4. **Identifying 'Z'**:
- The letter \( Z \) represents the slope of the line in the logarithmic plot. It indicates how much the species richness \( S \) increases for a unit increase in area \( A \). A higher \( Z \) value suggests a steeper increase in species richness with increasing area.

5. **Conclusion**:
- Therefore, in the context of the species-area relationship:
- \( C \) is the y-intercept (constant) of the equation.
- \( Z \) is the slope of the line.

### Final Answer:
- \( C \) is the y-intercept, and \( Z \) is the slope of the line in the species-area relationship equation.