Presumably whatever their nutrition and health requires, for instance, if a tree frog requires fruit flies to maintain a healthy and balanced diet, then the conservation center probably feeds their tree frogs fruit flies.
Commensalism. The fish is benefited and the sea urchin is not affected.
Considering the child's age and symptoms, it appears that this is an allergic reaction. It can be inferred that among the options, the food most likely to trigger these symptoms is peanut butter.
Peanut butter, in addition to having added sugar, hydrogenated or semi-hydrogenated fats, sodium and other additives, has proteins that our bodies recognize as "foreign" causing our immune system to react.
Peanut allergy is usually discovered in the early years of life, due to its high consumption in childhood, and especially affects babies and children who have asthma, rhinitis and sinus problems.
I think the answer should be:<span>D) Small Fish and other Aquatic Species
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In food pyramid, the biomass will be much lower in the higher level. In general, every level will have lower of mass/energy compared to the level below. Then, the greatest biomass should be found in the producer class. High-level consumer like bird or mammals should have the lowest mass.
But it was inverted in aquatic, producer become the lowest mass so phytoplankton and zooplankton must be lowest. You should be able to exclude option A and C so it is either option B or D. Since B has zooplankton, I prefer to choose D
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