To solve this problem, we need to identify the incorrect pair from the given options. Let's analyze each option:$\newline \bullet$Option 1: Alkaloids - Codeine$\newline$ - Alkaloids are naturally occurring chemical compounds that mostly contain basic nitrogen atoms.$\newline$ - Codeine is an alkaloid found in opium poppy and is used for its analgesic properties.$\newline$ - Therefore, this pair is correct.$\newline \bullet$Option 2: Toxin - Abrin$\newline$ - Abrin is a highly toxic protein found in the seeds of the plant Abrus precatorius (rosary pea).$\newline$ - It is indeed a toxin, so this pair is correct.$\newline \bullet$Option 3: Lectins - Concanavalin A$\newline$ - Lectins are proteins that bind to carbohydrates.$\newline$ - Concanavalin A is a lectin derived from the jack bean and is used in biochemical research.$\newline$ - Therefore, this pair is correct.$\newline \bullet$Option 4: Drugs - Ricin$\newline$ - Ricin is a highly toxic protein derived from the seeds of the castor oil plant, Ricinus communis.$\newline$ - It is not used as a drug due to its toxicity.$\newline$ - Therefore, this pair is incorrect.$\newline$Thus, the incorrect pair is Option 4: Drugs - Ricin.