Untitled

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    <title></title>
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    <header>
        <h1>Living Creatures</h1>
    </header>
    <section>
        <article class="birds">
            <h2 class="birds-heading">Birds</h2>
            <ul class="birds-list">
                <li class="bird">Nightingale</li>
                <li class="bird">Owl</li>
                <li class="bird">Hawk
                    <ul>
                        <li class="sub-bird">Black Hawk</li>
                        <li class="sub-bird">Chicago Hawk</li>
                    </ul>
                </li>
                <li id="eagle" class="bird">Eagle</li>
                <li class="bird">Sparrow</li>
                <li class="bird">Falcon</li>
                <li class="bird">Blackbird</li>
            </ul>
        </article>
        <article class="mammals">
            <h2 class="mammal-heading">Mammals</h2>
            <ol class="mammal-list">
                <li id="dolphin" class="mammal">Dolphin</li>
                <li class="mammal">Elephant</li>
                <li class="mammal">Hyena</li>
            </ol>
        </article>

    </section>
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