TASK DEFINITION: Given scientific fact as input, generate the question from this fact such that it can be answered from the input.
PROBLEM: The human body has as many as two trillion lymphocytes, and lymphocytes make up about 25% of all of leukocytes.

SOLUTION: The human body has as many as two trillion lymphocytes, and lymphocytes make up about 25% of all of what?

PROBLEM: Interstitial fluid are all hormones secreted into before entering the circulatory system.

SOLUTION: Where are all hormones secreted into before entering the circulatory system?

PROBLEM: Evolution that occurs over a short period of time is known as microevolution.

SOLUTION:
Evolution that occurs over a short period of time is known as what?