How can I get a few of the sub categories to show?

For example, say for my main (top level) category called "animals" and it has 50 different subcategories such as "cats", "dogs"...."zebras"

Now, how can I get a few of the sub categories to show under the main category on the home page? like this

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Animals (1542)
Cats, Dogs, Eagles...

Plants (543)
Grass, Trees, Flowers...

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how can I do this?

Thanks.