The accessory pigments like carotene & xanthophyll necessary to have in green plants is chlorophyll
Explanation:
Various pigments present in the plants helps in the absorption of the light, at photosynthesis. They acts as helpers to the plants. Chlorophyll helps in the green plants for absorption of light through which they can prepare their own food. The electrons in the molecular level of chemical structure of the pigment moves at certain energy levels. The chlorophyll is again divided into different types i.e. chlorophyll a,b,c,d. In case of plants chlorophyll a and chlorophyll b are the most important.
Because the definition of parasitism is living as a parasite on or in another organism and in this case the Aphids are living on the underside of the leaves. So i would go with Parasitism. If im wrong please forgive me :)
