Which factor is a biotic factor of an ecosystem? A)the bacteria that live in the intestine of a rabbit
B)the temperature of water in a stream
C)the rocks that provide cover for a rattlesnake
D)the amount of water vapor present in a rain forest
HELP PLSSS

Math each whole number with a rational, exponential expression

Afactory makes propeller drive shafts for ships. a quality assurance engineer at the factory needs to estimate the true mean length of the shafts. she randomly selects four drive shafts made at the factory, measures their lengths, and finds their sample mean to be 1000 mm. the lengths are known to follow a normal distribution whose standard deviation is 2 mm. calculate a 95% confidence interval for the true mean length of the shafts. input your answers for the margin of error, lower bound, and upper bound.

If the scale factor between two circles is 2x/5y what is the ratio of their areas?