Select the correct answer. What should you NOT do when doing abdominal workouts?
A.
Keep your chin off your chest
B.
Keep your head aligned with the spine
C.
Put pressure on your neck
D.
All of the above

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.