Give reason for the following (9*1=9 marks)
a)It is difficult to hold a school bag having a strap made of a thin and strong string.
b)An iron nail sinks in water.
c)A camel can run efficiently in the desert sand.
d)An army tank weighing more than a thousand tonnes rests upon a continuous chain.
e)Cutting tools have sharp edges.
f)A truck or motor bus has much wider tyres.
g)It is easier to swim in salt water than in freshwater.
h)The skydivers float in the air.
i)A block of plastic released under water comes up to the water's surface.