Use any or no and the words in the box: snow,petrol,teeth,big hills,legs,oxygen. 1.why is it easy to ride a bike in holland? because there 2.why don't people go skiing in the north of australia? because there isn' 3.why can't snakes run? because they've 4.why do astronauts need space-suits to survive on the moon? because there' 5.why are solar cars good for the environment? because they don't 6.why can't birds bite? because they've