You will be given a definition of a task first, then some input of the task.
In this task, you are given a sentence and a question, you would be asked to create the answer which is contained in the sentence provided.

Sentence: Characterized by a short lifespan, leukocytes begin with production in the bone marrow under the influence of csfs and interleukins. Question: Characterized by a short lifespan, what begin with production in the bone marrow under the influence of csfs and interleukins?
Output:
leukocytes