For
thea human being -- use the indefinite article "the" only when you are referring to a particular person or thing.
expectations from their
lifelives and...
Don't use too many "he or she". Stick with one! This is just an examination essay. No one will accuse you of gender bias.
things that make
s people
happy are dependent
to on age
because for a children, a toy makes them happy; for teenagers a car makes them happy.. -- the part in red is erroneous. I couldn't come up with a good suggestion. Revise it, and read it out loud to yourself.
To achieve happiness is not very hard but to defining happiness is very difficult.
Okay, here you are repeating yourself. Read the first line of the essay.
Always make it a point to leave at least five minutes for revision. It'll help weed out these things.
None of the wind can help a ship if it does not know the destination.
...awkwardly constructed sentence. Be careful while using metaphors. You won't get any marks for your creativity if you mess up the grammar.
I think these are enough corrections for one day.