In a convection current, why does cool air take the place of warmer air? 1.Cool air is denser than warm air, so it sinks to take the place of rising warm air.

2.Cool air is less dense than warm air, so it sinks to take the place of rising warm air.

3.Cool air is denser than warm air, so it rises to take the place of sinking warm air.

1.  Cool air is more dense than warm air so it sinks to take the place of the warm rising/buoyant air.

Explanation:

This is why heating a room with cold outside walls or glass windows (if budget can afford), we use warm radiant heaters at the floor level to break up the convection current/cold draft.  

As opposed to just diffusing air at the ceiling level, which is good in summer as cool air falls (air conditioning is in range of 55 to 65 degf out of the diffuser), mixing with warmer room air.

emily ruth's annual premium is $1058.50

step-by-step explanation:

emily ruth is a female of 27 years age purchasing 20 year endowment insurance with face value $25000.

from the given table,

for females, the age of a male 3 years younger should be used.

so, we have to check for 24 year male for 20 year endowment.

it is 42.34 for every $1000 face value.

for a face value of $25000,

it is 25 * 42.34 = $1058.50

∴ emily ruth's annual premium is $1058.50