Your answer would be valence electrons, i believe.
Antibiotic resistance is a consequence of evolution via natural selection. The antibiotic action is an environmental pressure; those bacteria which have a mutation allowing them to survive will live on to reproduce. They will then pass this trait to their offspring, which will be a fully resistant generation.
Let me try...
How about, grass, moose(moose eats grass), black fly(when moose dies it's eaten by fly), fish(fish can catch flies sometimes), and then Osprey(birds eat fish).
The second one... How about, grass, deer(deer eats grass), then wolf(eats deer), the mosquito(sucks wolf's blood), I don't know the dragon fly though
HOPE THAT HELPED SOMEWHAT :)
