What percentage of the Earth's surface is covered by oceans?

• Less than 50%

• Exactly 60%

• More than 70%

• About 30%

Which of the following best describes a sea?

• A large area of water surrounded by land.

• A strip of water that flows through many places.

• A smaller body of water found where land meets the ocean, and is part of the ocean.

• The world's longest river.

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What type of water do rivers primarily contain, making it suitable for drinking?

• Saltwater

• Brackish water

• Freshwater

• Mineral water

What is a key characteristic of lakes regarding their water source?

• They are always formed by underground water.

• They do not require a continuous source of new water.

• They need a continuous source of new water to prevent drying up.

• They are primarily fed by ocean tides.