DAY ONE: Radioactivity - the property of some elements like uranium or plutonium to emit rays that are harmful to all life.
DAY TWO:Cent - one one-hundredth or 1/100.
Sent - to cause to go (past tense.)
Scent - a smell, fragrance, or odor.
DAY THREE:Yore - time long past.
You're - contraction for you are.
Your - relating to ones self, shows possession.
DAY FOUR: Gaunt - being thin or bony, suffering from hunger or weariness.