最近突然喜欢上了Pitbull！！！想知道他的详细资料

最近突然喜欢上了Pitbull！！！想知道他的详细资料

pitbull 还是一个狗的品种 古巴出生，古巴人。 被乔治亚州的人收养，成为拉丁裔美国人。 没有和任何女人传过绯闻，估计是没有女朋友。

shark的资料英文

What is a Shark?

Sharks are a type of fish.

Sharks are amazing fish that have been around since long before the dinosaurs existed. They live in waters all over the world, in every ocean, and even in some rivers and lakes.

Unlike bony fish, sharks have no bones; their skeleton is made of cartilage, which is a tough, fibrous substance, not nearly as hard as bone. Sharks also have no swim bladder (unlike bony fish).

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MAJOR DIFFERENCES BETWEEN SHARKS AND BONY FISH

ATTRIBUTE SHARKS

BONY FISH

Skeleton Cartilage only Bones and cartilage

Swimming Can only swim forward. Can swim forwards and backwards

Buoyancy (floating) Large oily liver Gas-filled swim bladder

Gills Gill slits but no gill cover Covered gill slits

Reproduction Eggs fertilized in female's body. Eggs usually fertilized in the water.

Skin Rough, sandpaper-like placoid scales Slippery, overlapping scales

SIZE

A scuba diver above a Whale shark. The Whale shark is the largest fish in the world; the basking shark is the second largest fish.

There are many different species of sharks that range in size from the size of a person's hand to bigger than a bus. Fully-grown sharks range in size from 7 inches (18 cm) long (the Spined Pygmy shark), up to 50 feet (15 m) long (the Whale shark). Most sharks are intermediate in size, and are about the same size as people, 5-7 feet (1.5-2.1 m) long. Half of the 368 shark species are under 39 inches (1 m) long.

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BODY SHAPES

Sharks have a variety of body shapes. Most sharks have streamlined, torpedo-shaped bodies that glide easily through the water. Some bottom-dwelling sharks (e.g. the angelshark) have flattened bodies that allow them to hide in the sand of the ocean bed. Some sharks have an elongated body shape (e.g., cookiecutter sharks and wobbegongs). Sawsharks have elongated snouts, thresher sharks have a tremendously elongated upper tail fin which they use to stun prey, and hammerheads have extraordinarily wide heads. The goblin shark has a large, pointed protuberance on its head; its purpose is unknown.

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VARIETIES OF SHARKS

There are about 368 different species of sharks, which are divided into 30 families. These different families of sharks are very different in the way they look, live, and eat. They have different shapes, sizes, color, fins, teeth, habitat, diet, personality, method of reproduction, and other attributes. Some types of shark are very rare (like the great white shark and the megamouth) and some are quite common (like the dogfish shark and bull shark). Sharks belong to the group of cartilagenous fish, the Elasmobranchii, that includes the sharks, rays, and skates.

There are over 350 different species of sharks. The spiny dogfish shark is the most common shark