Read the following passage and mark the letter A, B, C or D to indicate the correct word or phrase that best fits each of the numbered blanks from 20 to 24. Fill in the appropriate word in question 20

Many animals in the wild are suspicious and fearful of human beings. Many animals would take escape instantly (20)_____________a human approaches. Man, however, soon discovered that some animals can be tamed or domesticate. Unlike animals in the wild, these animals would (21) _____________ man to come close to them. They would even allow their owners to stroke or pet them.

In the early times man would domesticate animals by setting traps to catch their young. A young  animal is (22) _____________  easily domesticated than an adult one. From young, the animal learns to trust and obey its owner.

Many different kinds of animals have been domesticate. Some common examples are animals like horses, elephants, chickens and pigs. The dog, which is also (23)_____________ as "man's best friend", is one of the first animals to have been domesticate. In England, long ago, the pig was a wild animal. It was a ferocious and aggressive (24)_____________ which was not easily capture. Yet nowadays, the domesticated pig is no longer the lean and tough than creature it used to be.