1. Introduction
  1.1 Background
  1.2 Research Objectives
2. Literature Review
  2.1 Definition of Intelligence
  2.2 Historical Perspectives on Intelligence
  2.3 The Nature vs. Nurture Debate
  2.4 Twin and Adoption Studies
  2.5 Family and Sibling Studies
  2.6 Genome-Wide Association Studies (GWAS)
  2.7 Candidate Gene Studies
3. Genetic Markers Associated with Intelligence
  3.1 Genes Implicated in Cognitive Abilities
  3.2 Genetic Variants and IQ Scores
  3.3 Gene-Environment Interactions
4. Methodology
  4.1 Data Collection and Analysis
  4.2 Selection Criteria for Studies
  4.3 Limitations and Considerations
5. Results and Discussion
  5.1 Overview of Findings
  5.2 Genetic Contributions to Intelligence
  5.3 Environmental Factors and Gene-Environment Interactions
  5.4 Implications for Education and Interventions