The answer to your question is either drawbridge or scaffolding. I want to go with drawbridge because it has support and stands of for itself, so its similar to a stucture if that makes sense.
The number of organsims at each levels, so there are more producer than herbivores, more herbivores than carnivores and so on...
Answer:
D. A brown gas produced
Explanation:
When a chemical reaction occur, there are several changes that takes place such as change in color, odor change, formation of a gas, and formation of a precipitate etcetera.
In the given chemical reaction, two colorless gas (NO and O2) react together and form brown gas (NO2). So, the change of gas from colorless to brown gas is the evidence that shows chemical reaction occurred.
Hence, the correct option is "D. A brown gas produced".
By mating with desired traits is your answer
