Whales are tetrapods--but living whales do not have four limbs. What is a more accurate way to describe tetrapods?

A) Animals that have at least two limbs
B) Animals that descended from a four-limbed ancestor
C) Animals that have four limbs at some point in their lives
D) Animals that evolved the ability to survive without limbs

I think your and is B) animals that descended from a four limbed ancestor.

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.