i) The colour of any plant depends on the pigments present inside that plant cell.

ii) The grass appears green due to the presence of chlorophyll which is a green coloured pigment present in the chloroplasts of the grass leaves.

iii) The papaya fruit appears yellow as it contains many chromoplasts which are filled with yellow coloured pigments like xanthophylls.

iv) The inside of a watermelon appears red in colour due to presence of the red coloured pigment known as lycopene in the edible part of the watermelon.