Identify the incorrect statement.
(i) Bacillus thuringiensis are available in sachets as dried spores which are mixed with kerosine and sprayed on to vulnerable plants
(ii) B. thuringiensis are used to control butterfly cateropillars, but leave other insects unharmed
(iii) The toxin of B. thuringiensis is rleased in the blood of larvae and the larvae get killed
(iv) By the development of methods of genetic engineering B. thuringiensis toxin genes have been introduced into plants.

Options

A. (i) and (ii)
B. (ii) and (iii)
C. (i) and (iii)
D. (ii) and (iv)

Answer

To identify the incorrect statement among the given options regarding Bacillus thuringiensis (B. thuringiensis), we will analyze each statement one by one.

### Step-by-Step Solution:

1. **Statement (i)**: "Bacillus thuringiensis are available in sachets as dried spores which are mixed with kerosene and sprayed on to vulnerable plants."
- **Analysis**: This statement is incorrect. B. thuringiensis is typically mixed with water, not kerosene, before being sprayed on plants. Therefore, this statement is false.

2. **Statement (ii)**: "B. thuringiensis are used to control butterfly caterpillars, but leave other insects unharmed."
- **Analysis**: This statement is correct. B. thuringiensis is known for its specificity in targeting certain pests, particularly caterpillars, while being harmless to other beneficial insects.

3. **Statement (iii)**: "The toxin of B. thuringiensis is released in the blood of larvae and the larvae get killed."
- **Analysis**: This statement is incorrect. The toxin is not released in the blood; it acts in the digestive tract of the larvae, causing cell lysis and ultimately leading to the death of the larvae. Therefore, this statement is false.

4. **Statement (iv)**: "By the development of methods of genetic engineering, B. thuringiensis toxin genes have been introduced into plants."
- **Analysis**: This statement is correct. Genetic engineering techniques have indeed been used to incorporate B. thuringiensis toxin genes into various plants, making them resistant to specific pests.

### Conclusion:
The incorrect statements are (i) and (iii). Therefore, the answer to the question is that both statements (i) and (iii) are incorrect.