List the three key factors of modern concept of evolution

Explanation

**Step-by-Step Text Solution:**

1. **Understanding Evolution**: Evolution is defined as a significant change that occurs over time within populations of organisms. It is a gradual process that involves small variations accumulating over long periods.

2. **Key Factor 1: Appearance of Genetic Variability**: The first key factor in the modern concept of evolution is the emergence of genetic variability. This variability arises from small changes in genes, which can occur due to mutations. Mutations are alterations in the DNA sequence that can happen during the replication process. These genetic variations are crucial as they provide the raw material for evolution.

3. **Key Factor 2: Spread of Genetic Variability by Differential Reproduction**: The second key factor is the spread of genetic variability through differential reproduction. This means that individuals with advantageous mutations are more likely to survive and reproduce compared to those without such mutations. The traits that enhance survival and reproduction are passed on to the next generation, leading to an increase in the frequency of these advantageous traits in the population over time.

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