One reason it was a health threat is it caused teeth to become ground down which would then lead to infections. The same was true with their eyes and lungs, sand would be blown into their eyes or inhaled into their lungs and then could cause infections.
Answer:
C. Varieties of an element that differ only in the number of neutrons are called isotopes.
Explanation:
The Earth is approximately
old. The solar system formed from giant gas clouds which was a part of the solar nebula.
The surface of soil which demarcates two soils of different geological ages is called a unconformity.
Palesol is the soil that lies between sediments or volcanic deposits. If the paleosol is older they have lithified rock.
Hence, option C is true.
Just needed some points :)
The correct answer is climax :)