Main Idea & Key Details Review

What is the main idea of the passage?

• Coral reefs are the most important ecosystems in the ocean.

• The ocean contains diverse ecosystems that support many different forms of life.

• Kelp forests grow faster than any other plant in the ocean.

• Hydrothermal vents are the most unusual places in the ocean.

Which detail supports the main idea by showing how coral reefs contribute to ocean biodiversity?

• Coral reefs cover less than 1% of the ocean floor.

• Coral polyps create hard skeletons around themselves.

• Coral reefs support about 25% of all marine species.

• Coral reefs are often called "rainforests of the sea".

What supporting detail explains how kelp forests benefit ocean animals?

• Kelp can grow up to 18 inches per day.

• Kelp forests provide habitat and food for many animals.

• Kelp can reach heights of over 150 feet.

• Sea urchins eat kelp as their main food source.

Which detail about hydrothermal vents supports the main idea about ocean ecosystem diversity?

• Hot water erupts from cracks in the ocean floor.

• These ecosystems exist without sunlight for energy.

• Bacteria convert chemicals into food energy.

• Unique species have adapted to these extreme environments.

How do the details about all three ecosystems work together to support the main idea?

• They show that all ocean ecosystems are being damaged by pollution.

• They explain how each ecosystem supports different types of marine life.

• They prove that coral reefs are more important than other ocean ecosystems.

• They describe how ocean ecosystems are all connected to each other.