Answer:
Nitrogenous bases contain the genetic information, their amount is variable among different species, and the arrangement of these bases is also variable among different species
Explanation:
Both Watson-Crick and Pauling's DNA models considered that DNA nitrogenous bases (i.e., Adenine, Cytosine, Thymine and Guanine) contain the genetic information that determines the characteristics of living organisms. Moreover, both DNA models also considered that nitrogenous base composition varies between species, as well as the arrangement of these bases in the DNA chain also varies between species. Based on these features, Linus Pauling considered that a model where nitrogenous bases would be arranged on the outside of the DNA molecule would be easier for the DNA molecule to be replicated, transcribed, or repaired. Although incorrect, Pauling's DNA triple helix model was fundamental to develop the helical (double-stranded) structure of DNA, which was finally discovered by Watson and Crick in 1953.
61% of emerging diseases is caused by zoonotic pathogens
Explanation:
Out of total emerging diseases zoonotic contributes 61%, that are originated from wildlife. The rate is increasing due to growth of human population, its mobility, frivolous, cultural and their socioeconomic purposes. Air is the major source for spread of infectious diseases. Zoonoses are generally caused by bacteria, viruses and pathogens that are blowout between animals and human beings. Modern zoonoses are Ebola virus and salmonella. One of such direct zoonoses is rabies, that is transformed directly from animal to human.
