In ecology<span>, a </span>niche<span> (</span>CanE<span>, </span><span><span>UK:</span> <span>/<span>ˈniːʃ</span>/</span></span><span> or </span><span><span>US:</span> <span>/<span>ˈnɪtʃ</span>/</span></span>)[1] is the fit of a species living under specific environmental conditions.
<span>https://en.wikipedia.org/wiki/Ecological_niche</span>
A. Cell membrane would be the answer.
C. Smaller societies rely more heavily on legislation and military forces.
The answer is B (example: color blindness)
As the main illness before you have a fever will normally be sore throat ( if you are heaty ) and flu ( if you caught a cold ) .
Hence the Doctors need to start monitoring the sore throats more carefully to prevent the increase of rheumatic fever cases .
Hope this helps !! :)