单选题在标准状态下，氧气和氦气气体温度相同，它们分子的平均动能<img border="0" alt="" src="https://tuku.weimei168.com/uploads/upimg/20251103/23818231_0.png">和平均平动动能<img border="0" alt="" src="https://tuku.weimei168.com/uploads/upimg/20251103/23818231_0_1.png">的关系为（　　）。<br/> <img border="0" alt="" src="https://tuku.weimei168.com/uploads/upimg/20251103/23818231_0_2.png">