Does the displacement of an object depend on the choice of the origin of the coordinate system?

When is an object said to be a particle?

Mark the wrong statement :-

Explain with an example that the magnitude of displacement may be zero but the corresponding path length is not zero.

$A$ boy walks uniformly along the sides of a rectangular park of size $400 \, m \times 300 \, m$,starting from one corner to the diagonally opposite corner. Which of the following statements is incorrect?

$A$ balloon is moving up in air vertically above a point $A$ on the ground. When it is at a height $h_{1}$,a girl standing at a distance $d$ (point $B$) from $A$ sees it at an angle $45^{\circ}$ with respect to the vertical. When the balloon climbs up a further height $h_{2}$,it is seen at an angle $60^{\circ}$ with respect to the vertical if the girl moves further by a distance $2.464d$ (point $C$). Then the height $h_{2}$ is (given $\tan 30^{\circ} = 0.5774$):