Question

choose the best answer.
red blood cells carry oxygen because they contain...

• hormones
• hemoglobin
• hemocytes
• plasma

correct answer: hemoglobin is a protein that attaches to oxygen and carries it throughout the body

Explanation:

The question is about the component in red blood cells that carries oxygen. Hormones are chemical messengers, hemocytes are cells in invertebrates, and plasma is the liquid part of blood. Hemoglobin is a protein in red blood cells that binds to oxygen and transports it.

Answer:

hemoglobin (the option with the green checkmark, as hemoglobin is the protein in red blood cells that attaches to oxygen and carries it throughout the body)