Answer 1

Accumulator :
(a) Accumulator is 8-bit main register in 8085, used to perform the arithmetical and logical operations. In such operations, one of the operand is always stored in accumulator.
(b) It can be used as both primary source and destination register. The final result of operation is also stored in accumulator.
(c) All data transfer between the CPU and I/O devices are performed through accumulator.
(d) Many memory reference instructions move data between the accumulator and memory