3 Identify the odd one giving reason.

• Coconut trees near a river bend towards the river.

• Root of trees near a well grows towards the well.

• Leaves of touch-me-not fold when we touch it.

• Roots of plants grow towards gravity.

• Leaves of touch-me-not fold when we touch it.

i.e. leaves of touch me not fold when we touch it. Leaves of Mimosa pudica fold because of the chemicals released.

Following options are not correct and the reason is as follows :

a) Coconut trees near a river bend towards the river so that there seeds can easily float in water and the coconuts can also travel a long distance.

b) Root of trees near a well grows towards the well as roots grow in the direction of water i.e. show positive hydrotropism.

c) Roots of plants grow towards gravity. Roots being positive hydrotropic are also positive geotropic which means that they grow freely in the direction of gravity.

* All these options lie in the same category because they are influenced by the physical factors whereas in case of touch me not plant chemical factors are involved.