Answer:
It's not atom it is an element Strontium.
An open system<span> is a system that has external interactions.</span>
Uhh how was your day or how is it going
Answer:
Gas
Explanation:
This is because a gas is the only substance in the given options which can be expanded or compressed as its particles are far away from each other. They can also take the shapes of the containers they are put in.
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