Express in words and mathematically the relationship between period and frequency

The wavelength and frequency of light are closely related. The higher the frequency, the shorter the wavelength. Because all light waves move through a vacuum at the same speed, the number of wave crests passing by a given point in one second depends on the wavelength. That number, also known as the frequency, will be larger for a short-wavelength wave than for a long-wavelength wave.

That is a hard question? srry

A., d., and f i think

100 pounds is 100 pounds no matter the object or item being weighed