Answer: Such constant change has characterized Earth since its beginning some 4.5 billion years ago. From the outset, heat and gravity shaped the evolution of the planet. These forces were gradually joined by the global effects of the emergence of life.
Explanation:
Crossing over contributes to genetic variation by exchanging chromosomal segments between non-sister chromatids of homologous chromosomes.
What is crossing over?
- Crossing over is the exchange and recombination of genetic components between the homologous chromosomes.
- This occurs in the pachytene stage of the meiosis-1 of the meiotic division.
- Crossing over occurs with the help of an enzyme and the enzyme responsible for crossing over is called Recombinase.
Thus, crossing over contributes to genetic variation by exchanging chromosomal segments between non-sister chromatids of the homologous chromosomes.
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