Which is the central metal ion in chlorophyll?

Assertion : $Rhoeo$ leaves contain anthocyanin pigments in epidermal cells.
Reason : Anthocyanins are accessory photosynthetic pigments.

What is the function performed by plant pigments?

Which of the following chlorophylls lacks a phytol tail?

Chlorophyll-$a$ and $b$ differ in having

Suppose there were plants that had a high concentration of Chlorophyll-$b$,but lacked Chlorophyll-$a$. Would they carry out photosynthesis? Then why do plants have Chlorophyll-$b$ and other accessory pigments?