In this task, you will be presented with a passage and have to answer a question based on your understanding of the events inferred from the passage. Try to find the best answer that is most likely to fill in "_". Note that the URLs in the text have been replaced with [Link].

(CNN) Your "BPA-free" plastic product may be no safer than the product it replaced, says a new UCLA study that analyzed the impact of a common BPA alternative on zebra fish embryos. The study joins a small but growing group of similar research sounding the alarm about so called "BPA-free" alternatives. "Our findings are frightening and important," said senior author and reproductive endocrinologist Nancy Wayne. "Consider it the aquatic version of the canary in the coal mine." After decades of animal research linked BPA (Bisphenol A), a known endocrine disruptor, to problems with brain and reproductive development, early puberty and a rise in breast and prostate cancer, many manufacturers stopped using the chemical to harden plastics, replacing it with "BPA-free" alternatives. The most common replacement is BPS (Bisphenol S), said Wayne.BPA-free alternatives may be no safer than BPA, say researchersMost common alternative, BPS, linked in study to disruptions of estrogen and thyroid hormones 
 Question:In addition to the effect on estrogen, the study also found both _ and BPS affected the thyroid hormone system.
BPA

Moscow (CNN) -- Russia's upper house of parliament voted Wednesday to revoke the right of President Vladimir Putin to use troops in Ukraine as efforts continue to calm a separatist uprising in Ukraine's east. The Federation Council had approved Putin's request for a resolution allowing the use of force on March 1. But Tuesday, Putin sent a letter to the speaker of the upper house seeking to cancel the resolution. One lawmaker voted against revoking the powers Wednesday, with 153 in favor. Putin's request was made in light of ongoing talks on how to settle the crisis in Ukraine's eastern regions, said presidential spokesman Dmitry Peskov.NATO agrees to a package of support to help Ukraine defend itselfRussia's Federation Council cancels resolution authorizing use of troops in UkrainePresident Vladimir Putin asked for the step in light of peace talks, his spokesman saysJohn Kerry and other NATO foreign ministers are meeting in Belgium 
 Question:The parliamentary action is a positive step, _ said, but it could be easily reversed.
John Kerry

New York (CNN) -- The U.S. population is expected to top out at close to 312.8 million people just around the time crowds gather to watch the ball drop on New Year's Eve, according to new census data released Thursday. The figure represents a 0.7% increase from last year, adding 2,250,129 people to the U.S. population since the start of 2011, and a 1.3% increase since Census Day, April 1, 2010. The agency estimates that beginning in January, one American will be born every eight seconds and one will die every 12 seconds. U.S.-bound immigrants are also expected to add one person every 46 seconds.Census Bureau: U.S. population is expected to be 312.8 million on New Year's DayThat figure represents a 0.7% increase from last yearLady Gaga, mayor to activate ball drop at Times Square on New Year's EveNYC has supplanted Las Vegas as the top New Year's destination, Priceline poll says 
 Question:On Thursday, officials conducted _'s annual "airworthiness test" -- a process in which confetti is tossed by handfuls above Times Square -- in preparation for the annual city tradition of dumping one ton of confetti over revelers in the iconic square.

New York