Name oxygen’s only vibration mode and briefly describe its vibrational motion.

Oxygen having only stretching mode of vibration as oxygen is present in form of O-O in which oxygen is bonded to other with single bond or O=O in which double bond is present in them and in O3, a double bond and single bond is present.

Hence, stretching vibration is present along with transitional mode of vibration

the correct answer would be b) volume versus temperature, because they are also directly proportional.