At present, scientists can determine the arrangement or relative positions of genes or DNA sequences on a chromosome. How does this knowledge benefit us? 1. It is possible to know the pedigree of livestock. 2. It is possible to understand the causes of all human diseases. 3. It is possible to develop disease-resistant animal breeds. Which of the statements given above is/are correct?

The correct answer is C because statements 1 and 3 are scientifically accurate applications of gene mapping, while statement 2 is an overstatement. Statement 1 is correct because knowing the DNA sequences allows scientists to track genetic inheritance and lineage in livestock, which is essential for breeding programs. Statement 2 is incorrect because not all human diseases are caused by genetics. Many diseases are caused by external factors such as bacteria, viruses, environmental pollution, and lifestyle choices. Even for genetic diseases, mapping alone does not immediately explain the complex interactions that cause the disease. Statement 3 is correct because identifying specific genes associated with immunity allows scientists to use selective breeding or genetic engineering to develop animals that are resistant to specific diseases. Therefore, only statements 1 and 3 are correct.