Answer:
The answer is Hg.
Explanation:
Symbol for Mercury is Hg.
Answer:- 3. 
and 
Explanations:- An empirical formula is the simplest whole number ratio of atoms of each element present in the molecule/compound.
For example, the molecular formula of benzene is 
. The ratio of C to H in it is 6:6 that could be simplified to 1:1. So, an empirical formula of benzene is CH.
In the first pair, the ratio of C to H in first molecule is 2:4 that could be simplified to 1:2 and the empirical formula is 
. In second molecule the ratio of C to H is 6:6 and it could be simplified to 1:1. and the empirical formula is CH. Empirical formulas are different for both the molecules of first pair and so it is not the right choice.
In second pair, C to H ratio in first molecule is 1:2, so the empirical formula is . The C to H ratio for second molecule is 1:4, so the empirical formula is 
. Here also, the empirical formulas are not same and hence it is also not the right choice.
In third pair, C to H ratio in first molecule is 1:3, so the empirical formula is . In second molecule the C to H ratio is 2:6 and it is simplified to 1:3. So, the empirical formula for this one is also . Hence. this is the correct choice.
In fourth pair, first molecule empirical formula is CH. Second molecule has 2:4 that is 1:2 mole ratio of C to H and so its empirical formula is . As the empirical formulas are different, it is not the right choice.
So, the only and only correct pair is the third one. 3. and
I think is true i took the test but im not sure what i put! Correct me if wrong
Answer : The correct option is, transverse wave.
Explanation :
Longitudinal waves : It is defined as the waves in which the particles of the medium move in the direction of the wave.
Transverse wave : It is defined as the waves in which the particles of the medium travel perpendicularly to the direction of the wave.
Surface wave : It is defined as a combination of transverse and longitudinal waves.
From the given image we conclude that, this illustration depict the transverse wave because the particles of the medium move perpendicularly to the direction of the wave.
Hence, the type of wave is, transverse wave
