I believe the answer is individuals. The drug side effect is the result of the interaction from the substance contained by the drugs and the environment in our body. It means that the effect will be influenced by the individual's age, weight, height, gender, etc.
Explanation:
Dear friend
How are you doing today I hope all is well with you and your family am writing this letter to you to tell you about my upcoming birthday celebration.
I going to have a great birthday celebration at the biggest event center in the Victoria Island and all my friends and family are going to be there so pls i beg you to attend the party
Your's sincerely
Dear friend