Why an offspring of a human is not a true copy of his parents in sexual reproduction?

In sexual reproduction, the offspring of a human is not a true copy of its parents due to several factors. Here are the steps to understand why:

1. Genetic Variation: During sexual reproduction, the parents contribute their genetic material to create a unique combination in the offspring. Each parent passes on half of their genetic information, resulting in a diverse set of genes in the offspring. This genetic variation leads to differences in physical traits, such as eye color, hair texture, and height.

2. Random Assortment of Chromosomes: In humans, the process of meiosis ensures that the offspring receives a random assortment of chromosomes from each parent. This means that the offspring may inherit different combinations of genes from their parents, further contributing to genetic diversity.

3. Crossing Over: Another factor that contributes to genetic variation is the process of crossing over. During meiosis, homologous chromosomes exchange genetic material, resulting in the shuffling of genes. This process further increases the diversity of the offspring's genetic makeup.

4. Mutations: Mutations, which are changes in the DNA sequence, can also occur during the formation of reproductive cells. These mutations can introduce new genetic variations in the offspring that are not present in either parent.

5. Environmental Factors: Apart from genetic factors, the environment also plays a role in shaping the characteristics of an individual. Factors such as nutrition, exposure to toxins, and lifestyle choices can influence the expression of genes and contribute to differences between parents and their offspring.

In conclusion, sexual reproduction introduces genetic variation through processes such as genetic recombination, crossing over, and mutations. These factors, along with environmental influences, contribute to the offspring being a unique individual and not a true copy of its parents.