Biome, though some might say ecosystem instead. Biomes are very large ecosystems that cover broad areas.<span>If they specify "one" reef, then they are probably looking for "ecosystem"</span>
Glucose or sugar are produced during photosynthesis.
A = (8,-3)
B = (1,8)
d = distance
––––––– ___
d(A,B) = √170 ≈ 13.0384
Hope this helps