The specialized cells that carry oxygen in our blood are called red blood cells, also known as erythrocytes.

Here's why:

* Hemoglobin: Red blood cells contain a protein called hemoglobin, which has a high affinity for oxygen. This means hemoglobin binds to oxygen in the lungs and releases it in the tissues where it's needed.

* Shape: Red blood cells have a biconcave disc shape, which increases their surface area and allows for efficient oxygen transport.

* No nucleus: Red blood cells lack a nucleus, which helps maximize space for hemoglobin.

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