The International Tennis Integrity Agency said the 29-year-old Oliveira was tested on Nov. 25 while competing at an ATP Challenger event in Manzanillo, Mexico and the A sample was positive for the ...

Tennis world rankings are calculated by the ATP, who award points based on a player's performance at particular tournaments. The further a player progresses in a sanctioned event, the more ...

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pH is a measure of how acidic or alkaline a solution is. The diagram below shows what happens to an enzyme when denaturation occurs. Each enzyme has an optimum pH but it also has a working range ...

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