To determine which statements about crossing over/genetic recombination are correct, we will analyze each statement one by one.
### Step-by-Step Solution:
1. **Statement I**: "It occurs in tetrad stage. It occurs in pachytene of prophase I of meiosis I."
- **Analysis**: This statement is correct. Crossing over occurs during the tetrad stage, which is when homologous chromosomes are paired up, and this occurs specifically during the pachytene stage of prophase I in meiosis I.
2. **Statement II**: "It occurs between non-sister chromatids of homologous chromosomes."
- **Analysis**: This statement is also correct. Crossing over happens between non-sister chromatids of homologous chromosomes, allowing for genetic material to be exchanged.
3. **Statement III**: "It is the exchange of genetic material between the homologous chromosomes."
- **Analysis**: This statement is correct. The essence of crossing over is the exchange of genetic material between homologous chromosomes, which contributes to genetic diversity.
4. **Statement IV**: "It is a recombinase enzyme mediated process."
- **Analysis**: This statement is correct. The process of crossing over is indeed mediated by recombinase enzymes, which facilitate the exchange of genetic material.
5. **Statement V**: "Recombination nodule of synaptonemal complex between the homologous chromosomes is the site of crossing over."
- **Analysis**: This statement is correct. The recombination nodules present in the synaptonemal complex are the sites where crossing over occurs.
6. **Statement VI**: "It causes genetic variation which is important for evolution."
- **Analysis**: This statement is correct. Crossing over introduces genetic variation, which is crucial for the process of evolution.
7. **Statement VII**: "It is also the reciprocal transfer of genes between the non-homologous chromosomes."
- **Analysis**: This statement is incorrect. Crossing over specifically occurs between homologous chromosomes, not non-homologous chromosomes. The transfer of genes between non-homologous chromosomes is a different process known as translocation.
### Conclusion:
The correct statements about crossing over/genetic recombination are I, II, III, IV, V, and VI. The only incorrect statement is VII.
### Final Answer:
The correct answer is that statements I, II, III, IV, V, and VI are correct, while statement VII is incorrect.
---
