The transgenic animals are those which have

Options

A. foreign RNA in all its cells
B. foreign DNA segment present in some of its cells
C. foreign DNA segment present in all its cells
D. both (A) and (B) .

Answer

To solve the question regarding transgenic animals, we need to understand the definition and characteristics of these organisms. Here’s a step-by-step breakdown of the solution:

### Step 1: Define Transgenic Animals
Transgenic animals are those that have had a foreign gene deliberately inserted into their genome. This process results in the expression of new traits or characteristics that are not naturally found in the species.

**Hint:** Think about what "transgenic" means in terms of gene transfer and modification.

### Step 2: Understand the Process of Creating Transgenic Animals
The most common method for creating transgenic animals involves the injection of DNA segments into fertilized eggs. This is typically done using techniques such as microinjection.

**Hint:** Consider the role of fertilized eggs in development and how they can incorporate new genetic material.

### Step 3: Describe the Development of the Organism
Once the foreign DNA is injected into the fertilized egg, the egg begins to divide mitotically. As the cells continue to divide, they all carry the newly introduced foreign DNA. This means that every cell in the resulting organism contains the transgene.

**Hint:** Focus on the concept of mitosis and how it leads to the propagation of the injected DNA throughout the organism.

### Step 4: Conclude the Characteristics of Transgenic Animals
Since all cells in the developed organism contain the foreign DNA, we can conclude that these animals express the traits associated with the transgene. Therefore, transgenic animals are characterized by the presence of foreign DNA in all their cells.

**Hint:** Reflect on how the presence of foreign DNA affects the traits and characteristics of the animal.

### Final Answer
Transgenic animals are those which have foreign DNA incorporated into their genome, resulting in the expression of new traits.

**Correct Option:** 3