Answer: I know how to do number 1:
Chico-un
persona-una
amigas-unas
hombres-unos
I don't understand what your saying
De que se trata tú pregunta? De algúna historia?
decomposers are the final stage of the food and they break down and eat what is dead already. if the decomposers wasn't apart of the food web then what ever is dead would sit there and rot and have this foul odor that wouldn't be pleasant at all to smell.