Final answer:
The extract from the seeds of Ulex europaeus is known as Lectin. It is used in saliva secretor testing due to its ability to bind to the H antigen present in the saliva of secretor individuals.
Step-by-step explanation:
The extract from the seeds of Ulex europaeus, a common plant used in saliva secretor testing, is known as d) Lectin. Lectins are proteins that have the ability to bind to specific carbohydrates on cells, which allows them to play a role in biological recognition phenomena. In this case, the Ulex europaeus Lectin is used because it binds to the H antigen present in the saliva of secretor individuals.
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