The ocean is a big, blue place full of amazing life. It covers about 71% of our planet! The ocean is home to many creatures like fish, whales, dolphins, and even tiny plants and animals that you can only see with a microscope. There are so many different kinds of life in the ocean that scientists think there are still many species we have not discovered yet.

One of the smallest creatures in the ocean is called phytoplankton. Phytoplankton are tiny plants that float in the water. They use sunlight to make food through a process called photosynthesis. This process helps produce oxygen, which is important for many sea animals. Without phytoplankton, there would be less oxygen in the ocean!

In addition to plants, there are also animals in the ocean. Some animals, like fish and whales, are called vertebrates. This means they have a backbone. Other animals, like jellyfish and crabs, are called invertebrates because they do not have a backbone. Both types of animals play important roles in the ocean ecosystem, which is a community of living things that interact with each other.

The ocean is also a home for some very large creatures. For example, the blue whale is the biggest animal on Earth and can grow as long as three school buses! On the other hand, there are also tiny creatures called microbes that are so small you need a special tool to see them. Even though they are tiny, they are very important for the health of the ocean.

Finally, the ocean is a place of change. Sometimes, the water gets warmer or colder, which can affect the animals living there. Some fish can swim long distances to find food or a better place to live. The ocean is always moving, and it is important for the planet's climate too.

1. What covers about 71% of our planet?

2. What tiny plants float in the ocean and help produce oxygen?

3. What are animals like fish and whales called because they have a backbone?

4. How long can a blue whale grow?

5. What happens to the ocean water sometimes that can affect the animals living there?