D. Decide if each of the following statement is true (T) or false (F)4. __ 1. The brain is the main organ of the circulatory system. __ 2. Blood is transported in the arteries and veins. __ 3. When the stomach does not function well.people will have digestive problems. __ 4. Our food is digested in the large intestines. __ 5. The muscle tissue of the heart is called skeletal tissue. __ 6. The spinal cord can control the activities of the muscles and organs. __ 7. Thyroid and pancreas are two kinds of glands. __ 8. When our immune system is weak, our body can be easily affected by bacteria and virus. __ 9. The fetus develops in the fallopian tube in about 9 months. __ 10. Bronchodilator is a kind of medicine related to treating respiratory system. __ 11. Urine is a kind of waste. __ 12. Urine is stored in the kidneys.

1. The brain is not part of the circulatory system; it is part of the nervous system.<br />2. Blood is indeed transported in the arteries and veins, which are part of the circulatory system.<br />3. The stomach plays a crucial role in digestion, and if it doesn't function well, digestive problems can occur.<br />4. Food is primarily digested in the small intestine, not the large intestine.<br />5. The heart's muscle tissue is called cardiac tissue, not skeletal tissue.<br />6. The spinal cord is part of the nervous system and can control the activities of muscles and organs.<br />7. The thyroid and pancreas are indeed two types of glands in the body.<br />8. A weak immune system makes the body more susceptible to infections from bacteria and viruses.<br />9. A fetus develops in the uterus, not the fallopian tube, and the gestation period is approximately 9 months.<br />10. A bronchodilator is a medication used to treat conditions of the respiratory system by dilating the bronchi.<br />11. Urine is a waste product produced by the kidneys and excreted by the urinary system.<br />12. Urine is produced by the kidneys but is stored in the bladder, not the kidneys.