You are asked to culture an unidentified sample of animal tissue. You notice that the cells seem to fail to exhibit density-dependent inhibition. The source of this tissue sample is most likely

Density-dependent inhibition refers to the phenomenon in which the crowded cells stop proliferating. In the process, the group of cells present in a region force competition for space, nourishment, and growth factors. Thus, when the cells are clumped together, they receive the signals to stop dividing further. Thus, in density-dependent inhibition, when the density is high no division of cells takes place.

Density-dependent inhibition is a process in which the growth of the cells is restrained to a specific limit of density, after that the growth gets prevented, probably due to cell-cell contacts. On the other hand, the tumor cells generally do not possess density-dependent inhibition, due to this, the cancer cells show unlimited growth without getting ceased. Therefore, in the given case, the source of the tissue sample is primarily a cancerous tumor.