Research indicates that using electronic devices before bed may make it difficult for people to fall asleep. the light appears to interfere with the body’s ability to create this hormone, which is responsible for sleep and wake cycles.

i don't think so because different teachers have different materials. tehy teach differently, unless you know for sure your teacher is the exact same as others. i would just contact ur teacher

exposure to hazardous carcinogens and toxic substances can cause breathing problems, such as copd and various types of cancer. it also increases the risk of heart attacks and strokes and has serious (but no less unattractive) side effects, such as aging, yellow teeth, a terrible smell and damage to the vocal cords.