A transport layer protocol has several responsibilities, One is to create a process-to-process (program-to-program) communication; TCP uses port (11) to accomplish this. Another responsibility of a transport layer protocol is to create a (12) and error-control mechanism at the transport level．TCP uses a sliding (13) protocol to achieve flow control．It uses the acknowledgment packet，time-out，and retransmission to achieve (14) control．The transport layer is also responsible for providing a connection mechanism for the application program．The application program sends (15) of data to the transport layer．It is the responsibility of the transport layer at the sending station to make a connection with the receiver．

A．procedure

B．function

C．route

D．flow

病原性出血和非病原性出血的不同是（）。

A、非病原性出血多处淋巴结有明显变化

B、病原性出血多处淋巴结无明显变化

C、病原性出血一般其他组织器官有炎症变化

D、非病原性出血一般其他组织器官无变化