Why do the load carrying heavy vehicles have large number of wheels ?

Why do the veins have valves?

All of the cells having large number of mitochondria except

Why do the blades of a pair of scissors have edges ?

Why do racer cars and birds have typical shape ?

Why do athletes like sprinters have a higher proportion of white muscle fibre?

Why do we have bring a small object near the eyes in order to see it clearly.

Draw all the possible structural formulae having molecular formula C_(6)H_(14) . Give names to all the isomers. Which difficulties were faced by you while naming? As the time progressed, the carbon compounds became very large in number and their common names caused confusion. A need was felt to have a logical system acceptable to all for naming the carbon compounds.

"_2 ^3 He and "_1 ^3H nuclei have the same mass number .Do they have the same binding energy?