A. making an observation.
Explanation:
When scientists use one of their five sense to gather information, they are simply making an observation.
Most physical properties of matter are studied using sense of taste, of feel, sight, hearing and smell.
- Observation is the act of making a measurement or studying.
- It helps to investigate particular phenomenon in nature.
- Most observations made with our senses are usually qualitative in nature.
- They cannot be assigned values like quantitative ones.
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Answer : The technology that can make coal a cleaner fuel is to use lower quality of coal with high sulfur content.
Explanation : Using lower quality of coal with high amount of sulfur in it can make coal a cleaner fuel because of high amount of sulfur it will have better combustion.
Answer:


Explanation:
Hello,
Based on the given undergoing chemical reaction is is rewritten below:

By stoichiometry we find the minimum mass of H2SO4 (in g) as shown below:

Moreover, mass of H2 gas (in g) would be produced by the complete reaction of the aluminum block turns out:

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B! because the hydrogen causes some nuclear reactions.