Chromosome no. 1 has the maximum number of genes among the human chromosomes.

Explanation:
- Chromosomes are structures made up of DNA and proteins that carry genetic information in the form of genes.
- Genes are segments of DNA that contain instructions for the production of proteins, which are essential for the functioning of cells and the body as a whole.
- Each human cell typically contains 46 chromosomes, including 22 pairs of autosomes (non-sex chromosomes) and one pair of sex chromosomes (XX in females and XY in males).
- The total number of genes in the human genome is estimated to be around 20,000-25,000.
- Among these chromosomes, chromosome no. 1 has the maximum number of genes.

Reasons why chromosome no. 1 has the maximum number of genes:
1. Length and size: Chromosome no. 1 is the largest human chromosome in terms of physical length and size. It contains approximately 249 million base pairs and spans about 8% of the total DNA in the genome.
2. Gene density: Chromosome no. 1 has a high gene density, meaning it contains a relatively large number of genes per unit length of DNA. This is due to the presence of many functional genes that are involved in various biological processes.
3. Gene duplications: Chromosome no. 1 has undergone numerous gene duplication events throughout evolution. Gene duplication is a process where a gene is copied and results in multiple copies of the same gene. This can contribute to an increased number of genes on a particular chromosome.
4. Functional significance: Chromosome no. 1 contains genes that play crucial roles in various biological functions, such as cell cycle regulation, immune response, metabolism, and development. These important functional genes may have been retained and accumulated on chromosome no. 1 during evolution.

In conclusion, chromosome no. 1 has the maximum number of genes among the human chromosomes due to its length, gene density, gene duplications, and the presence of functionally significant genes.