Read the article and choose the best answer (A-D) for the sentences (1-4)

Some people say that the best defense is a good offense; an octopus, however, would disagree. In addition to being one of the strangest and most beautiful creatures in nature, the octopus has some of the most inventive and effective defense mechanisms imaginable. While other animals have teeth, horns, or claws to help defend them from predators, the octopus concentrates its energy on hiding from and confusing its attackers. When it wants to get away, the octopus has an impressive arsenal of tricks at its disposal.

The most well-known of the octopus’s defense mechanisms is its ability to squirt clouds of ink into the water. Some octopi use this cloud of ink as camouflage; after squirting the ink, the octopus retreats into the ink cloud where the predator cannot see it. Other octopi use the ink cloud as a decoy. If a large, intelligent predator such as a shark knows that octopi use ink clouds for camouflage, it might simply attack the ink cloud blindly, hoping to make contact with the octopus inside. However, some sneaky octopi will release the ink cloud in one direction and scurry away in another direction, leaving the predator with nothing but a mouthful of ink. In addition to confusing predators’ sense of sight, these ink clouds also confuse their sense of smell. The ink is composed primarily of melanin (the same chemical that gives human skin its colour), which can shut down a predator’s sense of smell. If an octopus cannot be seen or smelled, it has a much higher chance of escaping an attack.

Another defense mechanism possessed by many octopi is the ability to change color, much like a chameleon. While most animals are always the same color, some species of octopi can control the amount of each colour pigment in their skin cells, allowing them to change colour. Some poisonous octopi, when provoked, will change their skin to a bright, eye-catching colour to warn predators that they are dangerous and ready to strike.

Other octopi use this ability to change their skin to the colour and texture of seaweed or coral, allowing them to blend in with their environment. The body of an octopus is highly flexible, and some species can combine this flexibility with their colour-changing skills to make themselves resemble more dangerous animals such as sea snakes or eels.

Yet another defense mechanism possessed by some octopi is the ability to perform an autotomy, or self-amputation, of one of their limbs and regrow it later. Many species of skink and lizard also possess this ability, which allows them to shed their tails when caught by a predator and therefore get away. When a predator catches a tentacle the octopus can amputate this tentacle, thereby unfettering itself, and regrow the tentacle later.

While the octopus may not be the most vicious creature in the ocean, its numerous and clever defense mechanisms help it to survive in the dangerous undersea world.

1. Which of the following sentences from the passage best expresses the main idea?

A The most well-known of the octopus’s defense mechanisms is its ability to squirt clouds of ink into the water.

B Some people say that the best defense is a good offense; an octopus, however, would disagree.

C Another defense mechanism possessed by many octopi is the ability to change colour, much like a chameleon.

D When it wants to get away, the octopus has an impressive arsenal of tricks at its disposal.

2. The author claims in paragraph 1 that an octopus would disagree with the statetment ‘the best defense is a good offense’ because

A octopi employ more defensive than offensive capabilities

B octopi possess good defensive and offensive capabilities

C octopi can protect themselves from teeth, horns, and claws

D not all octopi possess the same defense mechanisms

3. As used in paragraph 4, which of the following is the best synonym for unfettering?

A freeing B regrowing C amputating D sacrificing