Transportation in Animals and Plants

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)_____.