(c) : A- Artery : Carries blood from heart to different body parts. It is thick-walled and elastic. The flow of blood in it is intermittent. B - Capillary : Nutrients, hormones, gases etc. can diffuse into tissue cells through capillaries and vice versa. It is thin-walled, and only one layer thick resting on basement membrane. C - Vein : Brings blood from different body parts to the heart. It is thin-walled and acts as low-resistance conduct for blood flow. D - Pulmonary vein : Two pulmonary veins from each lung transport the oxygenated blood to the left atrium.