Shells are considered biotic because they come from living things. Biotic describes something living or use to be living such as plants and animals. So shells are considered biotic because they come from a living organism.
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Hope that helped:)
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Answer:
all of them you put are correct except the first one
Explanation:
pluto isn't considered a planet due to its size
hope this helps :)
Answer:
.
Explanation:
To explain the last sentence, what I mean by that is the sudden decrease in air pollution in just a few weeks is what would have typically taken multiple years to do. Due to less drivers, factories shutting down, and more, less toxic and infirm mental hazardous chemicals were released into the atmosphere in an extremely short amount of time. However, nowdays, it is almost back to where is was before the pandemic.
I would say (C) considering all of the others seem positive
Hope this was helpful!! :)