Assertion: Leaf colouration is due to the presence of four pigments – Chlorophyll a, chlorophyll b, xanthophylls, and carotenoids.
Reason: Chlorophyll b is the chief pigment associated with photosynthesis.
Answer & explanation
Correct answer: option 3
The correct answer is Option (3) - Assertion (A) is true and Reason (R) is false.
Chlorophyll a is found in all photosynthetic plants except bacteria. Hence, it is called a universal photosynthetic pigment.
It is also called primary photosynthetic pigment because it performs the primary reaction of photosynthesis which involves the conversion of light into chemical energy.
Other photosynthetic pigments like chlorophyll b, carotenes, and xanthophylls are called accessory pigments.