State whether true or false: The heart of birds is four chambered.
State whether the following statements are true or false. If false, correct them.
(a) Plants consume oxygen for respiration.
(b) Plants produce oxygen during the process of making their own food.
(c) Air helps in the movements of sailing yachts and gliders but plays no role in the flight of birds and aeroplanes.
(d) Air does not occupy any space.