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".
Hollow bones are always a disadvantage because it means that they are less sturdy and easier for predators to break.
Answer:
self-copying molecules ate the primordial soup
Explanation:
The answer is the bladder
