a tropic level is each of several hierarchical levels in an ecosystem, comprising organisms that share the same function in the food chain and the same nutritional relationship to the primary sources of energy.
hierarchical - of the nature of a hierarchy; arranged in order of rank.
organisms - the material structure of an individual life form.
primary - of chief importance; principal.
ecosystem - a biological community of interacting organisms and their physical environment.
Since it has 4 protons, it must have an atomic number of 4. (That makes it beryllium.) Since it has a 4 protons and 5 neutrons, it has a mass number of 9.
