Question

Why do you never see cattle or goats browsing on the weed calotropis?
A)The plant produces highly poisonous tannins.
B)The plant produces quinine which is bitter in taste
C)The plant produces cardiac glycosides
D)The plant bears prickles

Answer 1

Hint: Cattle and goats are the herbivores which feed on weeds, grasses and herbs. These animals are left on open fields for grazing. The animal too can destroy cultivated crops. These animals are selective feeders which do not eat the plant which is harmful for their health.

Complete answer:
The species of plants and animals which are being eaten by the other animal adapt a defence mechanism to protect themselves from falling into prey. Many animals have developed spinous exoskeleton which protects themselves from predators.
The herbs and small plants also adapt several morphological and chemical defence systems to protect it from the herbivorous animals. For example-
Calotropis- it is a poisonous plant which produces chemicals like caloyoxin, calactin etc. These are produced as milky juice from stem and leaves. These chemicals are cardiac glycosides. So it is also used as poison in an arrow.

1.The plant that produces highly poisonous tannins is witch Hazel.
2.The plant which produces quinine is cinchona.
3.The plant which bears prickles are cactus, rose, babbol, keekar etc,

Hence, the correct answer is option (C)

Note: The mouth of the herbivores is adapted to eat plants which bear prickles. For example camels. It is adapted for desert vegetation. The plants in the desert have leaves reduced to spines. The Camel has a thick jaw which helps to chew prickles.