The substance is a compound because it's formed by two different elements.
The answer is A: salt content
The explanations of natural phenomena, and additional hypothesis most often come about as a result of a scientific theory.
Explanation:
Scientific theory is a general explanation of natural phenomena developed through extensive and reproducible observations, more general and reliable than a hypothesis.
Then Every scientific theory starts as a hypothesis. A scientific hypothesis is a solution for an unexplained occurrence that does not fit into a currently accepted scientific theory. It must be based on careful rational examination of the facts.
In Spirogyra and allied forms the chloroplast<span> grows as the cell grows, and only divides when this divides.</span><span>
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