Why do sedimentary rocks have layers?

Which of the following is not a required characteristic of a well-written melody? variation in pitch shape lyrics phrase

How should i study korean, and how many hours should i study it? i am a high school student already learn japanese in class, also i play sports so i tend to not study korean much because i have an excuse, like, ‘i dont know how to properly study for korean’ 감사합니다

What is the potential danger from an accident at a nuclear power plant? a) fire and large scale explosions b) exposure to radiation c) meltdown of the plant and surrounding community d) entire cities could be wiped out