Answer:
Answer the following questions: What is the composition of air? Answer: Air is composed of nitrogen, oxygen, carbon dioxide, many other gases, water vapour and dust particles. Which gas in the atmosphere is essential for respiration?
Explanation:
Because they did not have the proper technology. Hope my answer was useful.
Answer:
The reverse of answer B
Explanation:
In a heterogeneous mixture the phases are clearly seen distinguished but a uniform single phase is seen in a homogeneous mixture
Answer:
Protons are positively charged. When a nucleus emits an alpha particle, these changes happen: the mass number decreases by 4. the atomic number decreases by 2.
Explanation:
One way is for <span>a landowner to gather as much information as possible about his or her private water well, to know how it works, as well as who has had the land before them. The landowner needs to see if anyone has used pesticides in the area, as it can contaminate the well water. This is the most common way. The landowner can also check to see if any other chemicals have been spilt in the area or even a gas or oil leak, as that too can cause the contamination of well water.
I hope this helps.</span>
