Answer:
a and d
Explanation:
a bromine and the calcium atom loses two elections
Question:
What's the article about?
D water expands when it freezes
Answer:

Explanation:
Hello,
In this case, due to the volume displacement caused the by the object's submersion, it's volume is:

In such a way, considering the mathematical definition of density, it turns out:

Rounding to the nearest tenth we finally obtain:

Regards.
You can't usually just use a single spectrum line to confirm the identity of an element because there are cases that the emission line id not clearly defined. When the emission line is very weak compared to surrounding noise, in which case the more datapoints you have to build up confidence for the existence of a particular emission spectra, the better.