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Comprehension: Read the following information carefully and answer the given questions. Octopuses are famous for their alien-like abilities, from regrowing damaged arms to changing their skin colour and texture. They use this colour-shifting power to camouflage and, interestingly, as a strange visual language to talk to other octopuses. A little known fact is they actually belong to a category of animals (phylum) called Mollusca, which is largely made up of snails. Yep, octopuses are like souped-up snails who lost their shells and grew a rather large brain. The greatest thing about them is their intelligence, which evolved completely independently from our own. Let’s consider their nervous system. Like us, octopus have large brains compared to their body size – easily the biggest of all invertebrates (animals without a backbone) and of comparable size to many vertebrates, such as frogs. It is, however, hard to compare brain size between marine animals and land animals, because the laws of physics differ in water and air. Animals are weightless in water but on land body shape and size is limited by gravity. An octopus brain is made up of about 500 million brain cells (neurons). This is seven times more than a mouse and about the same as a marmoset monkey. Humans, on the other hand, have 86 billion brain cells. Testing octopus intelligence can be a problem, because the animals frequently outsmart scientists. For example, scientists can struggle to get an octopus to solve a maze, because they often climb out and crawl over the top to reach their food reward. And that’s assuming they haven’t already escaped from their aquarium home and are crawling around the lab. Unlike us though, octopuses don’t live for very long. The giant Pacific octopus might live up to five years, but most live for just a year and some as little as six months. They hatch from eggs fully formed and ready to go. They never see their parents and have to learn everything on their own. Identify the correct statement from the following. I. Octopuses belong to a category of animals called Mollusca. II. It is hard to compare brain size between marine animals and land animals. III. Vertebrates are animals without a backbone.
