Logic Gates

Logic gates are of the lowest digital abstraction level which operates on 0s and 1s. (source for ref.: https://bjc.edc.org/bjc-r/cur/programming/6-computers/1-abstraction/01-abstraction.html).

Network (digital circuit) created out of logic gates is called Register-transfer Level (RTL). As it is created out of gates, it is also considered gate level. (no ref. source)

Automata is akin to a robot, i.e. a self-operating mechanism. (no ref. source)

Combinational CircuitSequential Circuit
No output feedback to inputHas output feedback to input
Multiplexer and EncoderRegisters and Flip-flops
source for ref: https://dare2compete.com/blog/difference-between-combinational-and-sequential-circuit