Tell us what’s happening:
When i run the tests it says that step 5 and 8 are wrong.
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You should have three section elements below your first p element
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Each section element should contain an iframe element as its third child.
I have checked the code, but I don’t see any problem with it. I also tried refreshing the page, but it still says it’s wrong. Can somebody help me find the problem?
Your code so far
<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="utf-8">
<title>Video Compilation Page</title>
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<body>
<main>
<h1>How to extract DNA from strawberries</h1>
<p>Extracting DNA from strawberries is a fun and educational experiment that makes the invisible visible—literally! Strawberries are perfect for this activity because they’re soft, juicily easy to mash, and — importantly — they’re octoploid, meaning they have eight copies of each chromosome. That translates to a lot more DNA per cell, giving you a satisfying and visible yield with simple kitchen tools
. By using everyday items like dish soap, salt, water, and cold alcohol, you can break open cells, release DNA, and make it clump into thread-like strands that you can actually see and handle — great for classrooms, demos, or just curious scientists at home.
</p>
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<section>
<h2>Materials</h2>
<p>Here are the materials we'll need for this experiment:
<ul>
<li>2–3 strawberries (fresh or thawed if frozen)</li>
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<li>Resealable plastic bag</li>
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<li>½ cup water</li>
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<li>1 tsp table salt</li>
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<li>1–2 tsp dishwashing liquid (clear soap works well)</li>
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<li>2 cups (or small beakers/cups)</li>
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<li>Coffee filter, cheesecloth, or paper towel</li>
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<li>Cold isopropyl alcohol or ethanol (chilled in freezer)</li>
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<li>Stirrer, coffee stick, or toothpick/tweezers</li>
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<em>Optional: funnel, measuring spoons, safety gear (goggles)</em>
</ul>
</p>
<iframe src="https://www.youtube.com/embed/JofXXyFZn38" title="Materials" height="320" width="450">
</iframe>
</section>
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<section>
<h2>Procedure </h2>
<p>Let's take a look at the steps:
<ol>
<li>Chill the alcohol in the freezer ahead of time to make DNA precipitate better.</li>
<li>Remove leaves from strawberries and place them in the plastic bag. Smash for ~2 minutes to break open cells.</li>
<li>In a cup, mix water, salt, and dish soap until salt dissolves. Pour into the bag and gently massage for 1 minute to create a lysis buffer.</li>
<li>Filter the strawberry mush through the coffee filter or cheesecloth into a clean container. This removes solid bits, leaving the DNA in solution.</li>
<li>Slowly pour the cold alcohol down the side of the container to form a separate layer on top. DNA will precipitate out, forming a whitish, fibrous layer at the interface.</li>
<li>Spool or lift the DNA threads using a stirrer or toothpick — that's your extracted strawberry DNA!</li>
</ol>
</p>
<iframe src="https://www.youtube.com/embed/JofXXyFZn38" title="Procedure" height="320" width="450">
</iframe>
</section>
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<section>
<h2>What's Happening & Safety Notes</h2>
<p><strong>Science behind the steps:</strong>
<ul>
<li>Smashing breaks open physical barriers (cell walls, membranes).</li>
<li>Soap/detergent dissolves cell and nuclear membranes by disrupting lipids.</li>
<li>Salt helps DNA strands clump together and detach from proteins.</li>
<li>Cold alcohol causes DNA to become insoluble and precipitate out of solution.</li>
<li>The result is actually chromatin — DNA mixed loosely with proteins — not perfectly pure DNA.</li>
</ul>
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<strong>Tips & safety:</strong>
<ul>
<li>Handle alcohol with care: it's flammable and irritating. Work in a ventilated area away from open flames.</li>
<li>Frozen strawberries can help further break down cells — thaw before using.</li>
<li>If purity is crucial (for advanced uses like PCR), this method may not suffice — it’s ideal for visual demonstration, not molecular analyses.</li>
</ul>
</p>
<iframe src="https://www.youtube.com/embed/JofXXyFZn38" title="Materials" height="320" width="450">
</iframe>
</section>
</main>
</body>
</html>
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Challenge Information:
Build a Video Compilation Page - Build a Video Compilation Page