Physics
Rectifiers are used to convert:

Direct current to Alternating current
Low voltage to high voltage
High voltage to low voltage
Alternating current to Direct current

ANSWER DOWNLOAD EXAMIANS APP

Physics
Thermohaline circulation is mainly due to

Warmer, less dense water sinking in the ocean and cold water replacing it
Warm water being added to the ocean due to industial waste
Cold, dense ocean water sinking and warmer water replacing it
Winds causing circulation of ocean water

ANSWER DOWNLOAD EXAMIANS APP