A and B are the two systems of control and coordination in the human body. The messages in system A are transmitted in the form of chemical substances C which travel comparatively slowly through the blood stream. The substances C are made in tissues D present in the head and trunk of human body. The messages in system B are transmitted very quickly in the form of electrical impulses through fibres E. The effect of messages transmitted by system B usually lasts for a much shorter time as compared to those transmitted by system A. (a) Name the system A. What does system A consist of ? (b) Name the chemical substance C. (c) What is tissue D ? Name any five such tissues in the human body. (d) Name the system B. What does system B consist of ? (e) Name the fibres E. (f) State whether system A controls the working of system B or system B controls the working of system A.