Which of the following outcomes can be concluded on the basis of Lederberg's replica plating experiment?

Options

A. Mutations are directed by enviroment
B. Genetic recombination is ultimate source of variation
C. Mutations are pre-adaptive
D. New enviroment induces mutation in poprlation

Answer

**Step-by-Step Solution:**

1. **Understanding Lederberg's Experiment**: Lederberg's replica plating experiment was conducted in 1952 to study mutations in bacteria. It demonstrated how mutations occur randomly and are not directed by environmental changes.

2. **Identifying the Key Outcome**: The key outcome of the experiment is that mutations are random events that can occur in a population, and these mutations can provide variations that may be beneficial for survival in changing environments.

3. **Evaluating the Options**:
- **Option 1**: "Mutations are directed by environment." - This is incorrect as Lederberg's experiment showed that mutations occur randomly and are not directed by environmental factors.
- **Option 2**: "Genetic recombination is the ultimate source of variation." - This statement is not a conclusion from Lederberg's experiment; it relates more to Darwin's theory.
- **Option 3**: "Mutations are pre-adaptive." - This is also incorrect because mutations are random and cannot be predicted to be beneficial before they occur.
- **Option 4**: "A new environment induces mutation in the population." - This statement is misleading as a new environment does not necessarily induce mutations; rather, it may select for existing mutations.

4. **Conclusion**: Based on the analysis of the options, the correct conclusion from Lederberg's replica plating experiment is that mutations are random and not directed by the environment.

**Final Answer**: The correct conclusion is that mutations are random events that can lead to variations in a population.

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