what does being a cold blooded animal mean?(英语解释,不要太长)

D
Both warm-blooded and cold-blooded desert animals have ways to escape the desert heat. Warm-blooded desert animals, such as rats and mice, rest during the day, often staying in cool underground burrows. At night they search for food. Animals that are out during the day, such as cold-blooded lizards and snakes, are active only for short periods. As their body temperature rises, these reptiles move into the shade in order to cool down. In the early evening, when the sun grows weaker, the reptiles become more active and begin their search for food again.
Getting enough water to survive is a major problem for all desert animals. Some desert animals, such as the kangaroo rat and the related jerboa, get water only from the food that they eat. Because these animals eat mainly dry seeds, they must survive on a tiny amount of water.
Most deserts have only a small number of frogs and toads because these animals must be near water to survive. Yet even these creatures have adapted to desert conditions. When small amounts of water collect in temporary streams, the desert-living frogs and toads become active. After a rainfall, they lay their eggs. The eggs grow into tadpoles in a few days and into adults in just four weeks. When the puddles dry up, the adult frogs or toads dig into the ground. Their metabolism(新陈代谢) slows, and they stay beneath the ground until the next rain, which may be as good as a year away. Until then, their bodily activities continue at a reduced rate.
The camel---often called the ship of the desert---is one of the most successful desert animals. Camels can go for long periods without water, but eventually they must drink. When water becomes available to them after a long drought, they may drink 95 liters of water or more. When water is not available, what helps camels survive the desert heat is the fat stored in their humps. A camel’s hump contains about 12 kilograms of fat. Fat is rich in hydrogen. As the fat is digested, hydrogen from the fat combines with oxygen in the air that the camel breathes. The result is H2O, or water. Each kilogram of fat that a camel digests produces about a liter of water.
71. Desert animals are usually more active at night because ______.
A. it is cooler at night B.it is easier to find water
C.they like the dark D. they are less likely to be attacked at night
72. Which of the following desert animals can get water only from the food?
A. The camel. B. The kangaroo rat. C. The frog.D. The toad
73. Which of the following is TRUE according to the passage?
A. All the desert animals rest during the day.
B. All the desert animals don’t rest during the day.
C. Cold-blooded desert animals don’t rest during the day.
D. None of the cold-blooded desert animals go out during the day.
74. The title for this passage could probably be ________.
A. Hot Deserts B. Desert Animals
C. How Desert Animals Get Water D. Ways To Escape the Desert Heat
75. The underlined word “burrows” in the first paragraph can be replaced by _________.
A. holes B. caves C. rooms D. Openings

Dolphins（海豚）are not fish, but warm-blooded animals. They live in groups, and speak to each other in their own language. In this, they are like other animals, such as bees and birds. But dolphins are very different from almost all land animals. Their brain is nearly the same size as our own, and they live a long time―at least twenty or thirty years. Like some animals, dolphins use sound to help them find their way around. They also make these sounds to talk to each other and to help them find food. We now know they do not use their ears to receive these sounds, but the lower part of the mouth, called the jaw.
Strangely, dolphins seem to like man, and for thousands of years there have been stories about the dolphin and its friendship with people.
There is a story about sailors in the 19th century. In a dangerous part of the sea off the coast of New Zealand, they learnt to look for a dolphin called Jack. From 1871 to 1903, Jack met every boat in the area and showed it the way. Then in 1903 a passenger on a boat called The Penguin shot and wounded Jack. He recovered and for nine years more continued to guide all ships through the area－except for The Penguin.
Today, some people continue to kill dolphins, but many countries of the world now protect them and in these places it is against the law to kill them.
小题1:Dolphins are different from many other animals in that they _____.

A．live in groups

B．have large brains

C．are warm-blooded

D．have their own language

小题2:Which of the following does the dolphin use to help it find its way around?

A．Its nose.

B．Its ears.

C．Its mouth.

D．Its eyes.

小题3:Why did the sailors off the coast of New Zealand look for Jack?

A．He was lonely and liked to be with people.

B．They enjoyed playing with him.

C．He was seriously wounded.

D．They wanted his help.

小题4:By telling the story of Jack, the writer wanted to show that _____.

A．dolphins are friendly and clever	B．people are cruel to animals
C．Jack is different from other dolphins	D．dolphins should be protected by law

Both warm-blooded and cold-blooded desert animals have ways to escape the desert heat. Warm-blooded desert animals, such as rats and mice, rest during the day, often staying in cool underground burrows. At night they search for food. Animals that are out during the day, such as cold-blooded lizards and snakes, are active only for short periods. As their body temperature rises, these reptiles move into the shade in order to cool down. In the early evening, when the sun grows weaker, the reptiles become more active and begin their search for food again.
Getting enough water to survive is a major problem for all desert animals. Some desert animals, such as the kangaroo rat and the related jerboa, get water only from the food that they eat. Because these animals eat mainly dry seeds, they must survive on a tiny amount of water.
Most deserts have only a small number of frogs and toads because these animals must be near water to survive. Yet even these creatures have adapted to desert conditions. When small amounts of water collect in temporary streams, the desert-living frogs and toads become active. After a rainfall, they lay their eggs. The eggs grow into tadpoles in a few days and into adults in just four weeks. When the puddles dry up, the adult frogs or toads dig into the ground. Their metabolism(新陈代谢) slows, and they stay beneath the ground until the next rain, which may be as good as a year away. Until then, their bodily activities continue at a reduced rate.
The camel---often called the ship of the desert---is one of the most successful desert animals. Camels can go for long periods without water, but eventually they must drink. When water becomes available to them after a long drought, they may drink 95 liters of water or more. When water is not available, what helps camels survive the desert heat is the fat stored in their humps. A camel’s hump contains about 12 kilograms of fat. Fat is rich in hydrogen. As the fat is digested, hydrogen from the fat combines with oxygen in the air that the camel breathes. The result is H2O, or water. Each kilogram of fat that a camel digests produces about a liter of water.
71. Desert animals are usually more active at night because ______.
A. it is cooler at night B.it is easier to find water
C.they like the dark D. they are less likely to be attacked at night
72. Which of the following desert animals can get water only from the food?
A. The camel. B. The kangaroo rat. C. The frog.D. The toad
73. Which of the following is TRUE according to the passage?
A. All the desert animals rest during the day.
B. All the desert animals don’t rest during the day.
C. Cold-blooded desert animals don’t rest during the day.
D. None of the cold-blooded desert animals go out during the day.
74. The title for this passage could probably be ________.
A. Hot Deserts B. Desert Animals
C. How Desert Animals Get Water D. Ways To Escape the Desert Heat
75. The underlined word “burrows” in the first paragraph can be replaced by _________.
A. holes B. caves C. rooms D. openings