Sea otters have no blubber. They stay warm with fur so thick that a million hairs grow in one square inch. Otters also guard kelp forests, eating the sea urchins that chew kelp to bare rock. What is the second main idea?

A honeybee that finds flowers dances on the comb. Her waggle tells the others which way to fly. One hive can hold thousands of workers. Bees also help farmers: pollen on their bodies rubs off on the next blossom. What detail shows that bees help crops?

Workers dug the Erie Canal across New York with hand tools and mules. The 363 mile ditch took eight years. When it opened in 1825, shipping grain east cost far less, and towns along the route grew fast. What is the best summary of this passage?

The male emperor penguin holds the egg on his feet for two months without eating. Thousands of males also huddle for warmth, and each bird takes a turn on the icy outside edge. What is the second main idea?

In 1980 Mount St. Helens blew apart, flattening forests and burying valleys in ash. Later, gophers mixed the ash with older soil, purple lupine took root, and young trees now cover the slopes. What is the second main idea?

A fact or example from one sentence that backs up the main idea is called a key ___.

Louis Braille was a teenager when he turned a soldier's dot code into a writing system. Six raised dots stand for one letter, and a reader feels them with a fingertip. This passage has two main ideas: how braille began and how it is read.

Giant sequoias grow only in California's Sierra Nevada, and some have lived more than two thousand years. Fire helps them too: bark two feet thick blocks the flames, and the heat pops cones open so seeds drop. What is the second main idea?

Monarchs fly three thousand miles south each fall. The trip takes several weeks. They land in fir forests in Mexico. Monarch caterpillars eat only milkweed, which leaves a bitter poison in their bodies. What detail shows that monarchs are hard to eat?

A flying bat squeaks and listens for echoes that tell it where a moth is. Bats are helpful neighbors too: one little brown bat eats thousands of insects a night, and desert bats carry pollen between agave flowers. What is the first main idea?

Read the passage: Maya's class planted a school garden, measured seedlings each week, and pulled weeds. By spring they had enough lettuce for a class salad. What is the main idea?

Which detail best supports this main idea: Polar bears are built to live in icy places?

Read the passage: Long ago, people used stars, landmarks, and hand-drawn maps to find their way. Today, phones can show a driver exactly when to turn. Even hikers can use satellite tools to check their location far from roads. What is the main idea?

True or False: The main idea is usually a small fact from just one sentence in a passage.

Read the passage: The library looked quiet but was full of activity: a chess club, homework help, and a librarian teaching safe searching. Families also checked out museum passes. What is the main idea?

Which sentence would be the best topic sentence for a paragraph with these details: It shades sidewalks on hot days. Its roots help hold soil in place. Its leaves can provide homes for insects and birds.

Read the passage: When the power went out, Grandma lit a lantern and pulled out an old recipe card. The family chopped vegetables, stirred soup, and told stories while it cooked. Everyone laughed more than usual. What is the main idea?

Which detail does NOT belong in a paragraph about how butterflies change during their life cycle?

Read the passage: Coach Rivera began practice by having players name one thing a teammate did well. Then the team practiced passing, listening to each other, and planning plays together. What is the main idea?

Which choice makes a summary strong?