Match the following:
Let us match each layer from Group-1 to its corresponding data unit in Group-2:
(A) Physical layer uses transmission units of individual bits: \(\Rightarrow\) e. Bit
(B) Data Link layer works with frames for error detection and framing: \(\Rightarrow\) d. Frame
(C) Network layer handles packets, often called datagrams: \(\Rightarrow\) b. Datagram
(D) Transport layer manages segments in protocols like TCP: \(\Rightarrow\) a. Segment
(E) Application layer deals with complete messages as seen by applications: \(\Rightarrow\) c. Message
In asynchronous transmission, the gap time between bytes is ________.
Digital signatures provide ________.
The surface integral \( \int_S x^2 \, dS \) over the upper hemisphere
\[ z = \sqrt{1 - x^2 - y^2} \]
with radius 1 is ..........