I want to say that the best option to go with will be species so option D.
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".
Answer:
All options are correct
Explanation:
Fossils are the remains of organisms (animals and plants) preserved in a rock. Scientists (geologists & palaebiologists) have used fossils to study the diversity of organisms in the past. This is based on their preserved morphological features. For example, several species of foraminifera has been identified in the rocks. Among them, some species are present today whereas others have become extinct.
Similarly, fossils are the indicators of past climate (e.g. temperature) as well. This means, if a specific species can survive at a particular temperature, its presence suggest that particular environment. For example, corals survive in tropical waters at specific depth and sunlight. So, if we find corals fossils, the cliamte of that particular age would be roughly the similar.
In the end, fossils can also provide evidence of orogeny (mountain building) process. These are typically plants fossils which cannot move and their remains are preserved in the folding rocks.
The answer is 60% are active
