<span>A. When is not answered.
(You could also argue that E: Where is not answered, although it is implied that it will be done nationally)
The sentence tells Who: The National Cereal Corporation, What: a free picture book, Where: Nationally, and Why: to promote reading</span>
Yes they can prevent possible life threatening diseases
D is the answerrr i think pretty sure
Answer:
hertz
Explanation:
Usually frequency is measured in the hertz unit, named in honor of the 19th-century German physicist Heinrich Rudolf Hertz. The hertz measurement, abbreviated Hz, is the number of waves that pass by per second. For example, an "A" note on a violin string vibrates at about 440 Hz (440 vibrations per second).
