Let's eliminate these one by one.
The first pair would not be the same, as X would most likely be in group IA, and Y would be in group VIIA, because of their tendency to gain and lose electrons.
The second pair would also violate the same rule, but X would most likely be in group IIA, and Y would most likely be in group VIA.
The third pair would not be the same, as X is most likely in group VIIA, and since Y has eight valence electrons, it is most likely a noble gas.
The final pair has X with atomic number 15, making it phosphorous. Phosphorous wants to gain 3 electrons to have a full octet of 8 outer "valence" electrons, and Y would also like to gain 3 electrons. This means it is possible that the final pair would be in the same group.
Ice floats on the surface of water 'cause <span>ice is less dense than water.
In short, Your Answer would be Option A
Hope this helps!</span>
Answer:
They mask the recessive alleles
0.24J/g*degC * 4.37g * 2.5degC = 2.622J
The 2.5 degC is the difference between 25 and 27.5 deg C.