Sexual Reproduction in Flowering Plants
When calyx and corolla are not distinguishable, then member of their collective whorl termed as
Correct Answer: Option(d)
Solution: A. Perianth can be defined as the non-reproductive part of the flower which consists of calyx and corolla and surrounds the sexual reproductive organ.
B. Sepals (calyx) are a modified form of leaves which form the outer whorl of a flower and protects the flower.
C. Petal (corolla) are also modified leaves which are often brightly coloured or with unusual shapes to attract pollinators.
D. Tepal is a term used when the sepals (calyx) and the petals (corolla) cannot be differentiated or classified easily.
So, the correct answer is 'Tepal'.