Note the relationship between the first two words and suggest a suitable word for the fourth place.
Organism from which common vector for cloning genes is derived : E.coli :: organism having toxic gene that kills insects :_______

Explanation

To solve the question, we need to analyze the relationship between the first two words and then find a suitable word for the fourth place based on that relationship.

**Step 1: Identify the relationship in the first pair of words.**
- The first pair is "Organism from which common vector for cloning genes is derived: E.coli."
- Here, E. coli is a bacterium that is commonly used as a vector in genetic engineering. Specifically, it provides plasmids, which are circular DNA molecules used to clone genes.

**Step 2: Determine the type of organism described in the second part.**
- The second part states: "organism having toxic gene that kills insects."
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