Air pollution; smoking in the house
        
             
        
        
        
Discovery of structure of DNA by Franklin and Watson and Crick.
Explanation:
Rosalind Franklin was researching about DNA structure at the King’s College at London based on x-ray diffraction studies; while, Crick and Watson were researching on the same at the Cambridge University based on Linus Pauling discovery of proteins.
Once when Watson happen to listen to Franklin’s lecture upon DNA structure and how it depends on relative humidity of the air and other facts relating to DNA; he along with Crick made physical DNA models which became a big failure.
Later, Franklin found that a wet form of DNA with high humidity had a helix like structure. This point became the base of later discovery of Watson and Crick’s double helix model of DNA along with the discovery of DNA molecules being made up of double chain of nucleotides. 
 
        
                    
             
        
        
        
Answer:
The bacterial DNA gets degraded at step 3 of the viral lytic cycle.
Explanation:
Viruses are organisms that are incapable of replicating on their own, hence, they require a living host which they infect and use its replicational ability to reproduce theirselves. The infection cycle of this virus is regarded as its replication cycle. Viruses employ either the LYTIC or LYSOGENIC cycle for infection.
The lytic cycle involves killing of their host cell at the end of the cycle. Generally, the cycle starts with the attachment of my the virus to the cell membrane of its host using specific receptor sites (step 1). It then penetrates the host cell as seen in step 2. 
After penetration, the virus then secretes certain degrading enzymes called ENDONUCLEASES that degrades the bacterial DNA. After which the virus uses the replicational and gene expressing ability of the host to transcibe its genetic material and replicate itself. This process called SYNTHESIS occurs in step 3. 
Hence, the yellow ring in the image that represents bacterial DNA disappears in step 3 (synthesis stage) because it gets degraded by viral digesting enzymes.
 
        
             
        
        
        
Answer:
grass deer wolf grizzly bear
430
Explanation: when calculating this you repeatingly divide by 10. If you going the other way you multiply by 10.