Suppose that the voltage is reduced by 10 percent (to 90 V). By what percentage is the power reduced

percent decrease in power  = 20 % .

Explanation:

Power P = v² / R where v is voltage and R is resistance which is constant .

taking log on both sides

log P = 2 log v - log R

differentiating on both sides

dP/P = 2 dv/v

-dP/P x 100 = 2 x -dv/v x 100

percent decrease in power = 2 x percent decrease in v ( voltage )

percent decrease in power = 2 x 10 = 20 %

a) cold, dry

explanation:

continental polar masses are cold and dry air masses because the cold air cannot hold much moisture. as they move into warmer air, they can trigger precipitation.

because growing process had stoped after 4-5 year