Why are accessory pigments like carotene & xanthophyll necessary to have in
green plants? what advantage do they provide

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.

i thinking chemical change

the two answers are a, the population of birds with large beaks will increase on the island, and c, the trait for large beaks will be passed on to future generations through natural selection. the reason for that is because if the birds that have beaks developed for eating small seeds lose all of their food, they will go hungry and eventually starve because they physically cannot eat the large seeds, therefore making the population of large beaked birds higher. also, if the trait of large beaks are dominant on the island over small beaks, then over time the large beaked birds will reproduce more and more, while the smaller beaked birds will reproduce less and less because they can't survive with the food provided. that leads to the trait of small beaks disappearing and the trait of large beaks taking over the island.