In this task, you are given a question and an answer, you would be asked to create the sentence based on the Question-Answer provided. It should be contained within the Question-Answer provided.

Question: What is the name of the blood protein that carries oxygen from the lungs to the body's assorted tissues? Answer: hemoglobin
Hemoglobin is the name of the blood protein that carries oxygen from the lungs to the body's assorted tissues.

Question: What is a measure that has both size and direction? Answer: vector
Vector is a measure that has both size and direction.

Question: Reversible reactions are indicated by what kinds of arrows? Answer: opposite-headed

Reversible reactions are indicated by opposite-headed kinds of arrows.