Is the process of translating a message received into understandable language or symbols.
a. encoding
b. decoding
c. observation
d. communication

Option B

Explanation:

The process of converting a message into a form where it can be transmitted as signals from the sender to the receiver is called as encoding. However, the process of the reconverting the encoded message into intelligible forms so that a receiver could understand the message is called as decoding. However, the entire process of encoding and decoding is known as communication.  

For example -  

In order to decode a sound signals, analogue from digital are retrieved.  

Hence, option B is correct

i do not know and i have a 100 in this class

white blood cells or wbc s are mainly 2 types-

1.agranulocytes

2.granulocytes

the monocytes or macrophages of agranulocytes , dendritic cells which are accessory leucocytes, and b cells which is one type of lymphocytes   identify the antigens present on the pathogen's surface. these three cells are called antigen presenting cells(apc) which are phagocytes and destroy the antigens by secreting antitoxins. besides this leukocyte is always plays vital role in the immunity of the body.