The nematode Caenorhabditis elegans has allowed scientists to develop "fate maps" tracing cell lines back to cell origins. The trait of nematodes and some other related groups where they have a set number of cell divisions leading to the same number of body cells in an adult is called:

A) anisogamy.

B) apoptosis.

C) cryptobiosis.

D) gastrulation.

E) eutely.

E. Eutely

Explanation:

Nematodes is also called Nemathelminthes. They are small slender worms and the head of a nematode is noticeable when compared to other parts of their body. The head is radially symmetrical while the body is bilaterally symmetrical.

Eutely is however the condition of having a body made up of a constant number of cells usually somatic cells like in the case of certain rotifers and lower worms.

The correct answer is E) eutely

Explanation:

Nematodes are organisms with bilateral symmetry, although their organs are coiled, sometimes one of the limbs is lost and many of sedentary life tend to radial symmetry. One of the most striking characteristics of these animals is that their growth is not produced by an increase in the number of cells that compose them, but by an increase in the size of the already existing cells; in fact, in most adult tissues the number of cells is constant, a phenomenon known as eutelia.

Eutelia is the condition of an organism composed of a constant number of cells or syncytial nuclei in all adult individuals of a species, such as nematodes, it means that body growth is not carried out by increasing the number of cells but by the growth of existing cells.