immune and digestive systems digestive and endocrine systems reproductive and immune systems endocrine and reproductive systems
I gave my students this multiple choice question: 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?

Only one answer is correct among these 4 choices:
- immune and digestive systems
- digestive and endocrine systems
- reproductive and immune systems
- endocrine and reproductive systems

Could you tell me which one is correct?

endocrine and reproductive systems