Read the following statements regarding evolution (A-D)-
A. Whales, bats, cheetah, and humans (all mammals) share similarities in the pattern of bones of forelimbs.
B. The diversity of life forms on earth has been changing over millions of years.
C. About 65 million years ago the dinosaurs suddenly disappeared from the earth.
D. A single-step large mutation is called speciation and explained by Herbert Spencer.
How many statements from the above is/are correct ?

Options

A. Four
B. Three
C. Two
D. One

Answer

To determine how many statements regarding evolution are correct, we will analyze each statement one by one.

### Step-by-Step Solution:

1. **Statement A**: "Whales, bats, cheetah, and humans (all mammals) share similarities in the pattern of bones of forelimbs."
- **Analysis**: This statement is true. All these mammals share a common ancestor, and their forelimbs exhibit homologous structures, meaning they have similar bone structures but may serve different functions (e.g., flying in bats, swimming in whales, running in cheetahs, and manipulation in humans).

2. **Statement B**: "The diversity of life forms on earth has been changing over millions of years."
- **Analysis**: This statement is also true. The diversity of life has indeed changed over millions of years due to processes such as evolution, natural selection, and extinction events. This reflects the dynamic nature of life on Earth.

3. **Statement C**: "About 65 million years ago the dinosaurs suddenly disappeared from the earth."
- **Analysis**: This statement is true as well. The mass extinction event that occurred around 65 million years ago, likely caused by an asteroid impact and volcanic activity, led to the sudden disappearance of the dinosaurs from Earth.

4. **Statement D**: "A single-step large mutation is called speciation and explained by Herbert Spencer."
- **Analysis**: This statement is false. The concept of a single-step large mutation leading to speciation is known as "saltation," and it was proposed by Hugo de Vries, not Herbert Spencer. Speciation typically involves gradual changes over time rather than a single large mutation.

### Conclusion:
After analyzing all four statements, we find that three statements (A, B, and C) are correct, while one statement (D) is incorrect.

**Final Answer**: 3 statements are correct.

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