Fill in the blanks.

1. The main organ of circulatory system is __________ in a human body.
2. In human body, blood containing oxygen is carried through __________.
3. The urine passed from the kidneys is stored in __________ in a human body.
4. Blood vessels that connect arteries and veins of the human body are __________.
5. Heart of human is protected by the __________.

Tick (√) the correct answer.

1. Number of kidneys in human body is
   1. 1
   2. 2
   3. 3
   4. 4
2. Which among the following carries pure blood?
   1. Arteries
   2. Veins
   3. Kidneys
   4. Ureters
3. The shape of human kidney is
   1. Semi-circle
   2. Bean
   3. Spherical
   4. None of these
4. The urine is passed from the kidneys through
   1. Ureters
   2. Urethra
   3. Urinary bladder
   4. Capillaries
5. Which among the following is the thinnest blood vessel?
   1. Artery
   2. Vein
   3. Capillary
   4. Ureter

State true or false.

1. Arteries carry blood from various parts of the body to the heart.
2. Veins carry impure blood.
3. Kidneys filter the waste in blood.
4. Ureter passes out the urine from the body.
5. Capillaries are parts of excretory system.