R Ram Sharma 🎓 Coach ⭐ 193.88K Points 📊 Biology Q. Yawning occurs- (A) due to excess concentration of CO2 in lungs (B) due to excess concentration of O2 in lungs (C) due to excess concentration of CO2 in blood (D) None of these 👁️ Show Answer 🔗 Share ⚡Menu ✅ Correct Answer: (C) due to excess concentration of CO2 in blood You must be Logged in to update hint/solution 💬 Discussion 💬 Comment