A:
Both are syllabaries, used to "spell" words rather than having a symbol that stands for a whole word or concept. Syllabaries relate to pronunciation. The Kanji characters do not.
Hiragana is a syllabary used to write words of traditional Japanese origin. The same words have Kanji characters that stand for them.
Katakana is a syllabary used to write borrowed words and words of foreign origin, such as names. It is more angular in appearance than Hiragana.
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