Select incorrect statement

Options

A. Orchid epiphytic on Mango is commensal
B. Bird laying eggs in the nest of another for incubation shows brood parasitism
C. Most animals and plants maintain a constant internal temperature
D. Small animals are rare in polar regions

Answer

To solve the question "Select the incorrect statement," we will analyze each of the provided options step by step.

### Step-by-Step Solution:

1. **Option A: Orchid epiphytic on mango is commensal.**
- **Analysis:** This statement describes the relationship between orchids and mango trees. Orchids that grow on mango trees benefit from the structure of the tree for support without harming it, which is a classic example of commensalism. Therefore, this statement is **correct**.

2. **Option B: Bird laying eggs in the nest of another for incubation shows brood parasitism.**
- **Analysis:** This statement accurately describes brood parasitism, where one bird species lays its eggs in the nest of another species, leaving the host to incubate and raise the chicks. This is a well-known behavior in some bird species. Thus, this statement is **correct**.

3. **Option C: Most animals and plants maintain a constant internal temperature.**
- **Analysis:** This statement refers to homeostasis, where many animals (especially warm-blooded animals) can regulate their internal body temperature regardless of external environmental conditions. This is a true statement, as many organisms do maintain a constant internal temperature. Hence, this statement is **correct**.

4. **Option D: Small animals are rare in polar regions.**
- **Analysis:** This statement is incorrect. According to Allen's rule, animals in colder climates tend to have shorter limbs and smaller body sizes, which helps them conserve heat. In fact, many small animals are adapted to polar environments. Therefore, this statement is **incorrect**.

### Conclusion:
The incorrect statement among the options provided is **Option D: Small animals are rare in polar regions.**

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