Transgenic animals have various applications, and they can be utilized to:

All of these

The correct answer is option (4) - All of these

Transgenic animals serve various important purposes in scientific research, offering valuable insights into different aspects of biology, medicine, and safety testing:

1. Normal physiology and development: Scientists can design transgenic animals to study gene regulation and how genes influence normal bodily functions and development. By introducing genes from other species that affect specific factors like insulin-like growth factor, researchers can understand their biological role in the body.
2. Study of disease: Many transgenic animals are created to investigate the contribution of genes to the development of diseases. These animals act as models for human diseases like cancer, cystic fibrosis, rheumatoid arthritis, and Alzheimer's, enabling the exploration of new treatments for these conditions.
3. Biological products: Transgenic animals can be engineered to produce valuable biological products. By introducing specific genes or DNA that codes for useful substances like human proteins (e.g., alpha-1-antitrypsin for emphysema treatment), these animals can produce these products, potentially offering more cost-effective and efficient treatments for certain diseases.
4. Vaccine safety: Transgenic mice are being developed to test the safety of vaccines before human use. By using these transgenic mice to assess the safety of vaccines, they may replace the use of monkeys in such tests, providing a more reliable and ethical alternative.
5. Chemical safety testing (Toxicity/safety testing): Transgenic animals are created with genes that make them more sensitive to toxic substances than non-transgenic animals. These animals are then exposed to these substances, allowing researchers to study their effects. This approach can yield toxicity testing results in less time, aiding in the assessment of chemical safety.

In summary, transgenic animals offer a wide range of applications, from advancing our understanding of normal biology and disease mechanisms to producing valuable biological products and facilitating safer and more efficient testing methods in various research areas.