<span>Other mutagens act by chemically modifying the bases of DNA. For example, nitrous acid (HNO2) reacts with bases that contain amino groups. Adenine is oxidatively deaminated to hypoxanthine, cytosine to uracil, and guanine to xanthine. ... Uracil pairs with adenine rather than with guanine.</span><span>
</span>
        
             
        
        
        
Hi,
Recombinant DNA technology is the process in which a target gene  of interest is replicated by inserting it into a vector and creating a recombinant DNA. This recombinant DNA is then returned into an expression system where it is replicated several times to give rise to multiple copies of our desired gene or that gene product.
One of the very important role for the execution of this technology is performed by Restriction endonuclease enzymes. These are the enzymes that have ability to cut the DNA fragment at specific sequence into fragments of different lengths called restriction fragments.
- They play a very important role in recombinant DNA technology:
- They can map the location of specific restriction sites where the target sequence is identified and cleaved.
- They cut down the DNA at specific sites called restriction sites. The host DNA in which foreign gene or target gene is inserted is also cut with the same restriction enzymes. So in the recombinant DNA technology, restriction enzymes act like a molecular scissor which identify and cut certain DNA sequences as per or requirement.
- The target sequence can be cut from multiple places by restriction enzymes since our target sequence can be present multiple times in the DNA of organism.
- When restriction enzymes cut the DNA, they leave sticky or blunt ends at that site in such a way that these ends are able to bind with the complementary bases of vector DNA when introduced.
- Then another enzyme DNA ligase seals the ends of target DNA and vector DNA making a whole recombinant DNA that is ready to be cloned and progress further steps of recombinant DNA technology.
<em>You can see attached image for better understanding.</em>
Hope it help!
 
        
             
        
        
        
Answer:
Pollen grains are also adapted for insect pollination. Some pollen grains are hairy or spiky, and others are sticky, so they attach to the insect. The anthers dangle in the breeze, and the pollen is blown away. The pollen grains are very small and light so they are easily carried on the wind.
Explanation:
hope it helps
 
        
             
        
        
        
<span>D. serotonin</span>
Neurotransmitter are biochemicals and compounds transported from one neuron to another.
Neurons are specialised cells that have dendrites, axons and terminal buttons that sends and receives stimuli from the environment and transduces it into a meaningful information and understand the complexities which the brain now functions. 
        
             
        
        
        
Answer:
Explanation:
The one characteristic that is true of those given is D. It occurs naturally.