Which activity is best described as a scientific endeavor? A. Designing devices astronauts can use to help them stay healthy
while in space
B. Developing a procedure for testing how extended stays in space
affect the human body
C. Performing tests on devices used by astronauts to ensure they
can be used safely
D. Creating a process for improving the design of equipment used to
monitor astronauts' health

Certain bacteria (such as aquaspirillum magnetotacticum) tend to swim toward the earth’s geographic north pole because they contain tiny particles, called magnetosomes, that are sensitive to a magnetic field. if a transmission line carrying 100 a is laid underwater, at what range of distances would the magnetic field from this line be great enough to interfere with the migration of these bacteria? (assume that a field less than 5% of the earth’s field would have little effect on the bacteria. take the earth’s field to be 5.0 * 10-5 t, and ignore the effects of the seawater.)