Main Idea

Read the following paragraphs Read the following paragraphs. Below each one are four sentences from the paragraph. Circle the letter of the sentence that is the main idea of the paragraph.

Birds are alike in many ways. All of them have backbones Birds are alike in many ways. All of them have backbones. All birds have two legs and two wings. All birds have feathers and lungs. Birds are warmblooded. Warmblooded means “their bodies are warm even when the weather is cold.”

All birds have feathers and lungs. Birds are alike in many ways. Birds are warmblooded. All birds have two legs and two wings.

Some birds, like the ostrich, are taller and heavier than a person Some birds, like the ostrich, are taller and heavier than a person. Some are very small, like the hummingbird. Many birds are good flyers. Other birds cannot fly at all. There are many different kinds of birds.

Some birds, like the ostrich, are taller and heavier than a person.

Many birds are good flyers.

There are many different kinds of birds.

Other birds cannot fly at all.

The outer feathers of birds form a smooth covering for their bodies The outer feathers of birds form a smooth covering for their bodies. The down feathers next to their bodies keep in body heat. Wing feathers are used for flying. Tail feathers help birds in balancing or steering. Not only does each feather type have a purpose, but the feathers can be replaced. Birds usually shed their old, worn-out feathers in the fall and grow a new set. Shedding of feathers is known as molting.

Tail feathers help birds in balancing or steering.

Shedding of feathers is known as molting.

Wing feathers are used for flying.

Not only does each feather type have a purpose, but the feathers can be replaced.

Birds weigh very little because their bones are thin-walled and hollow Birds weigh very little because their bones are thin-walled and hollow. Their feathers are also very light. Flying birds have powerful muscles attached to the breastbone. The bodies of most birds are built for flying.

Birds weigh very little because their bones are thin-walled and hollow.

Their feathers are also very light.

The bodies of most birds are built for flying.

Flying birds have powerful muscles attached to the breastbone.

Birds’ eggs must be kept warm Birds’ eggs must be kept warm. The baby bird grows inside the egg, eating up the food stored in the egg. By the time the food is used up, the bird fills the whole egg. Then it hatches. All birds develop in eggs. Large birds, such as ostriches, lay eggs that are often as large as six inches long. Tiny birds, such as hummingbirds, lay eggs that are only a quarter of an inch long.

Then it hatches.

Birds’ eggs must be kept warm.

Tiny birds, such as hummingbirds, lay eggs that are only a quarter of an inch long.

All birds develop in eggs.