The current in a wire is alternated once each second. What happens to the magnetic field around the wire? A.
It remains constant.
B.
It alternates in direction each second.
C.
There is no magnetic field. The alternating directions cancel out.
D.
The magnetic field rotates at a constant angular velocity.

unicellular organisms, like bacteria, are able to perform all life functions within one single cell. multicellular organisms need many different types of cells to carry out the same life processes. each of these special types of cells has a different structure that it perform a specific function.

wegner's theory did not explain how the continents could move

explanation: