On galapagos island Darwin observed variation in beaks of birds (Dawrin's finches) and he concluded :

Options

A. Inter species variation
B. Intraspecies variation
C. Natural selection according to food
D. Inheritance of acquired characters

Answer

### Step-by-Step Solution:

1. **Observation of Variations**: Charles Darwin observed variations in the beaks of birds, specifically the finches on the Galapagos Islands. These birds are commonly referred to as Darwin's finches.

2. **Understanding Natural Selection**: Darwin's conclusions were primarily based on the theory of natural selection, which suggests that organisms better adapted to their environment tend to survive and produce more offspring.

3. **Adaptive Radiation**: The variations in the beaks of these finches can be explained through the concept of adaptive radiation. This occurs when a single ancestor species rapidly diversifies into multiple forms to adapt to different environments or niches.

4. **Food Resource Influence**: The different shapes and sizes of the beaks in Darwin's finches correspond to the various food resources available on the Galapagos Islands. For instance, some finches evolved beaks suited for eating seeds, while others adapted to feed on insects or cactus.

5. **Conclusion**: Based on his observations and the evidence of natural selection, Darwin concluded that the variations in the beaks of the finches were a result of natural selection influenced by the availability of food resources.

6. **Correct Answer**: Among the options provided, the conclusion that best aligns with Darwin's observations is that the variations in the beaks of the finches were due to natural selection according to the food resources available.

### Final Answer:
The correct conclusion drawn by Darwin is that the variations in the beaks of the Darwin's finches were a result of natural selection influenced by available food resources.

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