Nicotine is a dangerous chemical found in cigarettes ; it is accompanied by two other very harmful chemicals. these are

Carbon Monoxide, Tar

Explanation:

Carbon Monoxide is a gas that is created when tobacco is burned, alongside with tar.

Tar is a sticky and black liquid that can cause health issues, and has many chemicals inside.

these are common warning signs of overtraining syndrome:

washed-out feeling, tired, drained, lack of energy

mild leg soreness, general aches, and pains

pain in muscles and joints

sudden drop in performance

insomnia

headaches

decreased immunity (increased number of colds, and sore throats)

decrease in training capacity/intensity

moodiness and irritability

depression

loss of enthusiasm for the sport

decreased appetite

increased incidence of injuries.

a compulsive need to exercise

answercobra of 1985;