Answer:
earth surface is uneven because land heats faster than water causes air to warm.,expand and rise over land while it cools and sinks over the cooler waters surface..
VALENCE ELECTRONS DETERMINE CHEMICAL PROPERTIES BECAUSE WHEN SAME ELEMENT REACT WITH DIFFERENT ELEMENTS THEN DIFFERENT COMPOUNDS ARE FORMING.FOR EXAMPLE HYDROGEN BOND WITH OXYGEN THEY FORM WATER AND WHEN HYDROGEN BOND WITH CHLORINE THEY FORM HCL WHICH SHOWS DIFFERENT PROPERTIES FROM WATER.