Provide your best answer for the following question. Give ONLY the answer, no other words or explanation.
For example:

Answer: <most likely answer, as short as possible; not a complete sentence, just the answer!>.

The question is: When specific hormones are present in the blood of a hen, an egg is released from an ovary. Which two systems are involved with the release of an egg?
endocrine and reproductive systems
Endocrine and reproductive.