Ans is C ,one gene contains one cistron and many Genes contains poly cistron.

Explanation:

The terms "gene" and "cistron" are sometimes used synonymously because they both refer to a specific segment of DNA that contains the information to code for a specific protein. However, there is a slight difference in their usage.

Difference between Gene and Cistron:

1. Gene: A gene is a functional unit of heredity that carries the genetic information necessary to produce a specific protein or RNA molecule. It is the basic unit of inheritance and is responsible for the transmission of traits from one generation to another. Genes are found in the DNA of an organism and determine its characteristics.

2. Cistron: A cistron is a segment of DNA that contains the coding sequence for a single polypeptide chain. It represents the smallest genetic unit that can undergo mutation. In simpler terms, a cistron is a part of a gene that codes for a specific protein.

Relationship between Gene and Cistron:

- In most cases, a gene contains multiple cistrons. This means that a single gene can have the coding information for multiple proteins.

- However, it is important to note that a cistron represents the coding sequence for a single polypeptide chain. So, within a gene, each cistron represents the coding information for a specific protein.

- Therefore, the correct answer to the given question is option 'C' - one gene contains one cistron. This means that each cistron within a gene codes for a specific protein.

- It is also worth mentioning that the terms "gene" and "cistron" are sometimes used interchangeably because they both refer to a segment of DNA that contains the coding information for a protein.

Conclusion:

In summary, while the terms "gene" and "cistron" are sometimes used synonymously, there is a difference in their usage. A gene is a functional unit of heredity that carries the genetic information, while a cistron represents the coding sequence for a specific protein within a gene.