Which of the following statements is/are correct with regard to the disadvantages of GM crops ?

Options

A. GM crops can affect human health by causing allergic reactions
B. Transgenes in commercial crops can endanger native species e.g., the Bt toxin gene expressed in pollen might endanger pollinators like honeybees
C. Production of GM crops causes damage to the natural environment and its always costly
D. all of these

Explanation

### Step-by-Step Text Solution:

1. **Understanding GM Crops**: Genetically modified (GM) crops are those whose genetic material has been altered using genetic engineering techniques. This modification is often done to enhance certain traits such as resistance to pests, improved nutritional content, or increased yield.

2. **Identifying Disadvantages**: The question asks us to identify the disadvantages associated with GM crops. Some known disadvantages include:
- Potential health risks, such as allergies due to foreign proteins introduced by genetic modification.
- Environmental concerns, including the risk of transgenes (genes that have been transferred from one organism to another) affecting native species and ecosystems.
- Economic factors, as GM crops can be more expensive to produce and may require specific conditions or inputs.

3. **Analyzing Statements**: We need to evaluate the provided statements regarding the disadvantages of GM crops:
- **Statement 1**: GM crops can affect human health by causing allergic reactions. This is correct because the introduction of foreign proteins can trigger allergies in some individuals.
- **Statement 2**: Transgenes can endanger native species. This is also correct, particularly if the GM crops produce toxins (like Bt toxin) that can harm non-target organisms such as pollinators.
- **Statement 3**: GM crop production can damage the natural environment and is often costly. This statement is correct as well, as the cultivation of GM crops can disrupt local ecosystems and may involve higher costs for farmers.

4. **Conclusion**: After analyzing the statements, we conclude that all the mentioned statements regarding the disadvantages of GM crops are correct. Therefore, the correct answer is that all options listed are disadvantages of GM crops.