Explanation:

Human Genome Project:
The Human Genome Project was an international research effort to determine the sequence of the human genome and to identify the genes that it contains. It was completed in 2003, providing a comprehensive map of the human genome.

Number of Genes:
- The Human Genome Project revealed that the number of genes in humans is actually less than 25,000.
- This finding was surprising at the time because it was initially estimated that humans could have as many as 100,000 genes.
- However, further research and analysis have shown that the actual number of protein-coding genes in the human genome is around 20,000 to 25,000.

Gene Function:
- Genes are segments of DNA that contain instructions for building proteins, which are essential for the structure and function of cells.
- Genes play a critical role in determining an individual's traits, such as eye color, height, and susceptibility to certain diseases.

Gene Regulation:
- In addition to protein-coding genes, the human genome also contains non-coding DNA that plays a role in regulating gene expression.
- Gene regulation is crucial for controlling when and where genes are turned on and off, which is essential for proper development and function of an organism.

Conclusion:
The Human Genome Project has provided valuable insights into the genetic makeup of humans, including the number of genes in the human genome. Despite initial estimates, the actual number of genes is less than 25,000, highlighting the complexity of gene regulation and the importance of non-coding DNA in controlling gene expression.