The chance that a human child will be born male is 50%
Each enzyme has a particular shape so that it can attach to a substrate (molecule). So, during a chemical reaction, the enzyme and substrate join together, and then the substrate is changed in some way depending what the chemical reaction is doing? hope this helps a little.
Edit.
Answer - Depending on the waves they must measure both at the same station in order to calculate and have knowledge of the interior of the earth.
Reasoning - S waves are sheer waves where as P waves are compressional which leads to both factors of understanding the strength and changes going on in the earth.