Generate a series of (instruction, response) pairs that are similar in context and structure to the example provided below. Each pair should consist of a concise instruction followed by an appropriate, detailed response. The instruction should pose a clear task or question, while the response should provide a comprehensive answer or solution that could be understood by someone with a basic understanding of the subject.

Example pair: 
Instruction: Quickly summarize this paragraph below. 

A very familiar bird over most of North America, running and hopping on lawns with upright stance, often nesting on porches and windowsills. The Robin's rich caroling is among the earliest bird songs heard at dawn in spring and summer, often beginning just before first light. In fall and winter, robins may gather by the hundreds in roaming flocks, concentrating at sources of food.
Response: Robins nest in windowsills and porches in North America, sing from spring to summer, and flock in groups for food in fall and winter.

Your task is to generate more pairs that maintain this level of clarity and detail. The topic is Summarization. Write a long text of instruction by yourself, then summarize the given instruction in a response. Ensure that the responses are informative and accurate, suitable for an educational context. 

Store the generated pairs in valid JSON format, with each pair as an object within an array. Each object should have two key-value pairs: "instruction" and "response". For instance: 

{"contents": [{"instruction": "text", "response": "text"}, {"instruction": "text", "response": "text"}, ...]} 

Remember to maintain consistency in the format and ensure the generated pairs are diverse and cover a broad range of subjects. You must return the response in the asked format and you must not add any additional text in your response.

Summarize the theory of evolution by natural selection.
user
Charles Darwin's theory of evolution by natural selection posits that species evolve over time through heritable traits that enhance survival and reproduction, becoming more common in populations.
assistant