I believe it's A!!! ( Hoped I helped️)
Answer: The correct answers are 1) Endocytosis and 2) Receptors are specific for the cells.
White blood cells are specialized cells of the immune system. They play important role in protecting body from foreign agents like bacteria . For this, they recognize the bacteria and forms a covering around it, pinching off the vacuole. By this, the cell performs a process called as Endocytosis ( specifically phogocytosis).
The receptors present on the white blood cells are quite specific. Due to this, they recognize specific foreign particles. For example B- cells produce antibodies which bind to specific antigens ( foreign protein) and therefore mount specific immune response. In other words, specific foreign particles are recognized by specific white blood cell. This indicates that the receptors on these cells are specific.
Thus, the correct answer is 1) Endocytosis and 2) Receptors are specific for the cells.
Question is incomplete, the complete question is as follows :
Clotting begins when a _________ occurs in a blood vessel wall. Almost immediately, _______ cling to the blood vessel wall and release _____________ which helps to decrease blood loss by constricting the vessel. __________ is also released by damaged cells in the area. This chemical substance causes ________to be converted to ____________. Once present, thrombin acts as an enzyme to atatch ___________molecules together to form long, threadlike strands of _________, which then traps ____________ flowing by in the blood.
Answer:
Clotting begins when a <u>BREAK</u> occurs in a blood vessel wall. Almost immediately, <u>PLATELETS</u> cling to the blood vessel wall and release <u>SEROTONIN</u>, which helps to decrease blood loss by constricting the vessel. <u>THROMBOPLASTIN</u> is also released by damaged cells in the area. This chemical substance causes <u>PROTHROMBIN</u> to be converted to <u>THROMBIN</u>. Once present, thrombin acts as an enzyme to attach <u>FIBRINOGEN</u> molecules together to form long, threadlike strands of <u>FIBRIN</u>, which then traps<u> ERYTHROCYTES </u>flowing by in the blood.