The phrase "a necessity appears" is correct and usable in written English.
It can be used when indicating that a need or requirement has become evident or noticeable in a particular context.
Example: "As the project progressed, a necessity appears for additional resources to meet the deadlines."
Alternatives: "a need arises" or "a requirement emerges".
While financial support is a necessity, it appears that having students from multiple professions is not critical for a valuable training experience; staff from different professions and students from a single profession can work successfully together.
As in those old 50's textbooks, necessity appears to breed invention, instead of the other way around.
The so-far fruitless search for unconventional weapons -- the primary justification for invading Iraq -- undermined his credibility, making what Mr. Bush described as a war of necessity appear to have been one of choice.
Which could only be true in the early days of the RNA world, however we have seen that such a metabolic system by necessity appeared late (the author also suggest that the code appeared late, se 1st paragraph of the "Relation to the abiotic and early metabolism" section).
A prolonged 'recovery from student life' possibly out of financial necessity appeared to influence attitudes to further training and, in turn, limit options in respect of 'preparation for the future'.
But on Monday, as the ratings agency Fitch downgraded Cyprus debt to "junk" status, prompted by the amount of rescue money that would be needed to bail out its banks, economic necessity appeared to trump all other considerations.
Patients' concerns about their treatments and their beliefs in its necessity appear to be critical in understanding patient adherence practices.
Though not a necessity, height certainly appears advantageous.
Before that became a necessity, a vision appeared.
"If there appears a necessity for an adjustment in the Portuguese programme we would be ready to do that," Schäuble said.
