Specific dye bind to specific nucleotides.
DDT stands for dichloro-diphenyl-trichloroethane. The first kind of synthetic/artificial insecticides came into use in the 1940s. The earlier usage of DDT include: a) Killing of malarial vectors, b) Combatting Typhus and other insect borne human diseases, c) As a pest control in crops d) as a pest control in garden, live stock production and even at homes.
The negative impact of DDT could be felt for the first time when the pests that were earlier killed by use of DDT have now become pesticides resistant. In the 1950s in USA, the regulatory measures were adopted to reduce the usage of DDTs as its effects as a pesticides were no more long significant and also it was creating detrimental physical and psychological impacts on the human and environment.
It was in 1972 that the U.S. Environmental Protection Agency cancelled the order for banning the usage of DDT based on the adverse impact it produced on the environment, human and other life forms. Since then continuous studies are being conducted to analyse the impact of DDTs. In some later years it was established that DDT is the cause of producing tumors in liver.
Some of the common negative impacts produced by DDT as per the U.S. Department of Agriculture :
a) The non destructive nature – DDT can not be destroyed and thus it remains persistent in the atmosphere
b) It attacks the tissues of living organisms especially the animals and humans ( fatty tissue)
c) It can penetrate the atmosphere to deeper extent.
Now as per the current stuation, The use of DDT is controlled and other alternatives of pest control organisms is being deduced. As per the treaty of Stockholm Convention on POPs (Persistent organic pollutants) , usage of DDT for malarial control is justified but it puts a restrictive use of DDT as pesticides in other areas.
I believe option B would be the correct choice because, without a catalyst, the reaction will be either too slow or will not happen at all as it would not acquire a fitting activation energy for the reaction.
If you would like to know why the other options are incorrect, please read on:
Option A is incorrect because since proteins are specific in nature, so other protein cannot be replaced, for some other chemical reaction.
Option C is not correct it is a genetic defect that the protein does not form, and all cells are genetically identical, a reaction cannot take place in any parts of the body.
And finally, option D would be wrong because if a forward reaction does not take place, a backwards reaction will not occur.
I hope this answer has helped, and I apologise if somehow this answer finds itself to be incorrect. Good luck on your quiz or homework. :)
<span>B. the creation of two daughter cells with half the number of chromosomes that the parent cell has by the process of cell division
</span><span>D. The exchange of solute molecules across a permeable membrane from areas of high concentration to areas of low concentration
</span><span>A. Osmosis occurs through a semipermeable membrane. Diffusion occurs through a permeable membrane.</span>
