4. Which statements accurately describe cell diversity?                                                              
a) Mycoplasmas are the smallest cells, about 0.3 µm in length.
b) Typical bacteria are much larger, around 10-20 µm.
c) The largest isolated single cell is a human nerve cell.
d) Human red blood cells are about 7.0 mm in diameter.
e) Nerve cells are some of the longest cells.
f) Cell shapes can be disc-like, polygonal, columnar, or irregular.
g) The shape of a cell is independent of the function it performs.