"possible challenges" is correct and usable in written English.
It can be used to refer to possible obstacles, difficulties, tests, etc., that may arise in a given situation. For example, "We have identified a few possible challenges that may arise in the implementation of this new policy."
There are many possible challenges in determining the possibility-probability equation.
Professor Kmiec said the opinion would lay the groundwork for a series of possible challenges by the Bush campaign.
These government insiders are able to advise if policy ideas are economically feasible, and on possible challenges to implementation.
According to research from charity Working Families, 90% of employers already offered this, but now all businesses face the possible challenges of managing a flexible team.
But, in a sign of the possible challenges involved in attracting young readers to print, the government said the primary outlet for the ads would be the Internet.
Despite the possible challenges for Huawei and ZTE, both companies say Europe remains a much friendlier place for them to do business than the United States.
But a diplomat has to engage with these groups – because they are possible challenges to the nation that he/she represents.
Civil rights groups are worried about possible challenges of voter eligibility, saying Secretary of State Glenda Hood, a Republican appointee of Governor Bush, has not done enough to prevent frivolous challenges.
"Most principals will kind of take a look at their communities and make a determination, given the possible challenges that those schools have had with disruptions during Halloween day".
The poll finds 42 percent of Republican voters supporting it, while 46 percent do not, underscoring possible challenges Republican candidates may face in an effort to strike a balance between the two.
Some possible challenges and future research were also discussed [4].
