This secretes chemicals that break down fats in the small intestine

Bile emulsifies

Explanation:

(breaks into small particles)  lipids (fats), which aids in the mechanical digestion of fats.   The pancreas and gland cells of the small intestine secrete digestive  enzymes that chemically break down complex food molecules into simpler ones.

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

i agree d is most definitely correct!