Physics
Ventilators are provided near the ceiling of the room because

These provide some sunlight in the room
These provide cross ventilation in the room
These do not look nice in the lower part
The exhaled warmer air rises up and goes out

ANSWER DOWNLOAD EXAMIANS APP

Physics
It takes much longer to cook food in the hills than in the plains, because

n the hills the atmospheric pressure is lower than that in the plains and therefore water boils at a temperature lower than 100oC causing an increase in cooking time
in the hills the humidity is high and therefore a lot of heat is absorbed by the atmosphere leaving very little heat for cooking
in the hills the atmospheric density is low and therefore a lot of heat is lost to the atmosphere
due to low atmospheric pressure on the hills, the water boils at a temperature higher than 100oC and therefore water takes longer to boil

ANSWER DOWNLOAD EXAMIANS APP