Atomic.
No, "multiple" is not a prefix. It is a standalone word that means having or involving several parts, elements, or individuals.
Gubernatorial is a word that means having to do with a governor.
There is no suffix in the word menarche. It is a compound neo-Latin word having two Greek elements: men- for month; and arche for beginning.
It means having to do with excretion.
The word you are looking for is "synthesize." It means to combine different elements or ideas to create a unified whole.
regarding
"Expertise" is a word that means having specialized knowledge in a specific field or subject.
Costal. This word should not be confused with "coastal" which means on the coast.
"Vigor" is a word that means having a lot of energy or enthusiasm.
No, the word 'compound' does not mean having only one part. In English literature the word compound means having at least two independent words.
Military
bellicose