Veins allow blood to flow only towards the ______.
Heart:
Final Answer: Veins allow blood to flow only towards the heart.
Veins have valves which allow blood to flow only in one direction. Arteries do not have valves. Yet the blood flows in one direction only. Can you explain why?
Fill in the blanks of the following paragraph using just two words – arteries and veins
___(a)___ carry oxygen-rich blood from the heart to all parts of the body and ___ (b)___ carry carbon dioxide-rich blood from all parts of the body back to the heart. ___ (c)___ have thin walls and ___ (d)___ have thick elastic walls. Blood flows at high pressure in ___ (e)___. Valves are present in ___ (f) ___ which allow blood to flow only towards the heart. ___ (g)___ divide into smaller vessels. These vessels further divide into extremely thin tubes called capillaries. The capillaries join up to form ___ (h)___.
Veins have valves to prevent the backflow of blood because the blood in veins flow ________.