Answer:
Worms that survived produced offspring that were resistant to the insecticide. 
 
        
             
        
        
        
Answer:
I think you're referring to the Metaphase...
Explanation:
During Cell Division (or, rather before!) the DNA needs to be replicated. This normally is done by DNA Polymerase, and results in two identical double strands (the "Sister Chromatids".
These chromatids are held together at the Centromere, which will be the heart of the "X"-shape. After that the DNA is packed into Chromosomes by winding it around proteins called Histones. If I remember correctly there are 5 different Histones.
This "Zipping Up" makes the chromosomes more visible.
As the two sister chromatids are still connected, the result is the X-shaped Metaphase Chromosome....
 
        
             
        
        
        
Answer:
The producers play main role in the food chain and food web as well. These organism make food by the help of the process known as photosynthesis.
Only producers have the ability to make food by trapping sunlight. All the living source needs energy to survive.
The source of food is producers so living things cannot survive without food. So there producers are considered as the main component of food chains and food web.
hence, they play a very vital role in the environment.