Topic sentence -

The skeletal system is important when protecting the human body.

Example -

Our cranium protects our brain and our ribcage protects our vital organs in our torso.

Xplain further -

Without these strong protective bones, our organs could be harmed. Imagine if your organs were on the outside of your body, what do you think would happen?

Tie up -

The 206 bones in the human body are like a knights shield protecting whatever danger comes its way.

Topic sentence -bone marrow is a squishy substance that is created inside your bones

Explain - yellow bone marrow is made of mostly fat cells. And your red marrow is made of blood cells. Yellow bone marrow will slowly evolved into cartilage.  

Xplain further - You start to lose red bone marrow as you get older. As you lose red bone marrow your body will start to build up carbon dioxide and creating pressure.

Tie up - human and animal both eat bone marrow.

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Example -

Xplain further -

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