2, because a theory is not a law that can not be changed, and new evidence can change a theory.
Argyroneta aquatica because it is the only species of spider that lives entirely uder water
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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