题目内容：
根据以下资料，回答题：Drink from plastic bottles can raise the body's levels of a controversial "gender-bending" chemical by more than two thirds, according to tests．
Experts have been concerned about the possible health effects of bisphenolA (BPA．--an everyday chemical used in many plastic food and drink containers and tins as well as clear baby bottles--which is officially classified as toxic in some countries．A study found that participants who drank for a week from polycarbonate (聚碳酸酯) bottles showed a 69 percent increase in their urine (尿液) of BPA．
Researchers did not say how much liquid was drunk per day．Researchers from Harvard School ofPublic Health studied 77 students, who had first undergone a seven-day "washout" phase in which theydrank all cold beverages (饮料) from stainless steel bottles in order to minimise BPA exposure．
They were then given two polycarbonate bottles and asked to drink all cold beverages from themduring the next week．Previous studies have suggested that high levels of BPA consumption are linked tobirth defects, growth problems and an increased risk of heart disease．In particular there are fears thatheating the bottles, as parents would do when warming their baby's milk, causes the chemical to leak inpotentially dangerous quantities into the liquid contained within．
"If you heat those bottles, as is the case with baby bottles, we would expect the levels to beconsiderably higher．This would be of concern since infants may be particularly susceptible to BPA'shormone gland-disrupting (扰乱腺体极速分泌) potential．" said the senior author of the latest study, Karin B．Michels．
Most adults carry BPA in their bodies but expert opinion on the risks is divided．The European Food Safety Authority believes that people naturally convert the chemical into less harmful substances in the body．
Previous studies had found that BPA could leach (渗出 ) from polycarbonate bottles into theircontents, but this study is the first to show the size of the corresponding increase in urinary BPAconcentrations in humans．
Harvard researcher Jenny Carwile said, "While previous studies have demonstrated that BPA is linkedto adverse health effects, this study fills in a missing piece of the puzzle--whether or not polycarbonateplastic bottles are an important contributor to the amount of BPA in the body．"
What do we know about bisphenol A (BPA．from the beginning of the passage? A．It is certain substance taken in by human beings every day．
B．It is a component contained in a number of plastic products．
C．It is an element that plays a decisive role in people's gender．
D．It is a kind of chemical that is universally regarded poisonous．
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