B may d answer 4 following question
Decomposers are essential in breaking down organic matter into useful ones. For the nitrogen cycle, they break down bodies of dead organisms turning it into ammonia. Also, some bacteria break down nitrates turning into nitrogen which goes back to air.
One fourth means (one half) of (one half) .
So the 18 months must be two half-lifes.
The half-life of this particular isotope is 9 months.
Answer: 1. The Bill of Rights
2. The Alien and Sedition Acts
Explanation:
Answer is: a secretary smokes a cigarette in a crowded break room.
External cost Is when consuming a good or servise imposes a cost to a third party. In this case, smoking affects other people in break room, causing pollution and health related problems.