Carbon-14 is used to determine the time an organism was living. the amount of carbon-14 an organism has is constant with the atmosphere, but when an organism dies the carbon-14 decays at a half-life of 5,730 years. if an archeologist measured the amount of carbon-14 in an organism and it was 25% of the total amount of atmospheric c-14, what is the age of the organism? 1432.5 years 5,730 years 11,460 years 17,190 years

=11,460 years

The initial amount was 100 %, which decayed to 25 %

Thus;  New amount = Original amount × (1/2)^n; where n is the number of half lives.

Hence;  25 = 100 × (1/2)^n

           =  1/4 = (1/2)^ n

          n = 2   (number of half lives)

Thus; the time will be; 5730 × 2 = 11,460 years

  = 11,460 years

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.

see the picture for the vector

the magnitude of the vector by pythagorean theorem

r = √( (-10)^2 + (3)^2 ) = √109

magnitude = √109 units

the direction angle between vector and x-axis is

tan^(-1)(3/10) = 16.699

so the direction is approximately 16.7 degrees north of west