Explanation:
physical exertion.
lack of physical activity.
lack of sleep.
being overweight or obese.
periods of emotional stress.
boredom.
grief.
taking certain medications, such as antidepressants or sedatives.
Electromagnetic waves do not require a medium to travel through. They can travel through empty space or matter.
Among the given choices, the ionic compound is D. Magnesium Chloride (<span>MgCl2</span>) where magnesium has a +2 charge while chloride has a -1 charge. Ionic compounds are chemical compounds comprising of ions held together by electrostatic forces named as ionic bonding.