The mutagens that result in cancer damage DNA by (b) weakening the DNA strand or interfering with base pairing. This mutagens are called carcinogens, if they cause a damage to <span>a gene that makes a </span>DNA<span> repair protein, it means that a cell will have less ability to repair itself, and ,as a result, this will lead to formation of cancer.</span>
        
                    
             
        
        
        
Answer:
Both gene expression and DNA micro array study about the expression of gene during different stages of development. 
Explanation:
The main purpose of gene expression studies is to determine the level of mRNA expressed at different stages of transcription in a tissue or at different stages of cellular development. If a gene is not “ON” during synthesis of RNA and protein, then the desired proteins are not produced. Such studies allow us to turn on such genes.  
DNA microarray  assays easily identify and determine the network of gene expression across the entire genome. The common application of DNA microarray include – mutation analysis and detection, assessment of gene cop, immunoassays etc.
 
        
             
        
        
        
The extermination of the dinosaurs, the start of a rise to dominance of mammals and a meteorite effect in mexico marks the boundary among the mesozoic and the cenozoic or as named as the k-p boundary. In addition, the cretaceous paleogene (K–Pg) boundary which is previously recognized as the cretaceous tertiary (K–T) boundary is a geological signature typically a thin band of rock.