CSS past papers · 2025
CSS 2025 Botany Past Paper
Download and review the CSS 2025 Botany Past Paper on CSS Vista, with archive details, related papers and a direct PDF link for examination preparation.
Paper details
- Examination
- CSS
- Year
- 2025
- Subject
- Botany
- Paper
- Single Paper
- Subject type
- Optional
- Mode
- Subjective
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Questions recorded from this paper
These 7 question wordings are transcribed from CSS Vista’s structured Botany past-paper record for CSS 2025.
- Q8 · fertilization(a) Discuss the stages of embryonic development in angiosperms, highlighting key (10) events in the formation of the embryo sac and zygote. (b) What is double fertilization in angiosperms? Discuss its significance and the (10) development of the endosperm.
- Q2 · Mechanism of oxidative phosphorylationHow does the chemiosmotic theory explain ATP synthesis during oxidative (20) phosphorylation? What is the significance of the proton gradient across the inner mitochondrial membrane?
- Q4 · Causes and reclamation of soil salinity and water logging in PakistanWhat are the primary causes of soil salinity and waterlogging in Pakistan? How do (20) these issues impact agricultural productivity? Discuss with reference to specific regions and irrigation practices. Evaluate the effectiveness of government policies and initiatives in addressing waterlogging and salinity in Pakistan.
- Q3 · Gene interactionDescribe the interaction between cytokinins and auxins in regulating plant growth (20) and development, with specific examples of their synergistic and antagonistic effects.
- Q6 · Evolution(a) What are chromosomes? Explain their structure and role in inheritance. (10) (b) Discuss the various mechanisms of genetic variability in fungi and their (10) significance in fungal evolution.
- Q7 · EvolutionHow do convergent and divergent evolutions differ? Provide examples from nature. (20) Also, describe the processes of genetic drift, gene flow, and mutation, and their contributions to evolution.
- Q5 · Genetic engineering and its applicationExplain the role of molecular techniques in the diagnosis, identification, and (20) management of plant pathogens. Provide specific examples of their application in Pakistan.