Automation System
Light sensors:

work in direct sunlight
cannot be used a s limit switches.
None of these
come in a wide variety of mounting styles
never use infrared light as light source

ANSWER DOWNLOAD EXAMIANS APP

Automation System
Stepping motors:

can run at varying speeds
can be built to index different amounts by changing the pole configuration
can run both clockwise and counterclockwise
do not require commutators
All of these

ANSWER DOWNLOAD EXAMIANS APP

Automation System
A venturi tube:

is made only of metal
can be used to measure gas or liquid flow rates
is extremely difficult to use
None of these
measures the presence of a liquid

ANSWER DOWNLOAD EXAMIANS APP