Which feature of electromagnets makes them more useful than permanent magnets in many modern technologies?
A. Electromagnets are not dependent on a power supply.
B. The strength of the magnetic field is more consistent in
electromagnets.
C. Electromagnets cannot be turned on and off.
D. The current can be adjusted to control the strength of the
magnetic field.

It is reasonable to assume that the bulk modulus of blood is about the same as that of water (2.2 gpa). as one goes deeper and deeper in the ocean, the pressure increases by 10000 pa for every meter below the surface. if a diver goes down 80.0 m in the ocean, by how much does each cubic centimeter of her blood change in volume? give the answer in cubic centimeters (actually one cubic centimeter equals one milliliter).