Pushing, pulling is the answer
The sentence can be completed as follows:
The wavelength of an electromagnetic waves is the spatial distance between two successive troughs.
Note that the wavelength of a wave can also measured as the spatial distance between two successive crests of the wave. Also note that the second part of the sentence ("also known as the period") is not true, because period is another thing (in fact, the period is the time interval between two successive troughs).
"The" (and any subsequent words) was ignored because we limit queries to 32 words.
Answer:
my name is Deepika Pandey anion I am 9 years old my father name is Dinesh Pandey my name is and my sister name is sister name is a
Heroin is the number 1 most addictive substance.