Regeneration in planarians depends on the presence of stem cells called neoblasts. These cells are distributed throughout the body and, when part of the worm has been amputated, they are activated to reform the tissues that have been removed.
Some reasons:
→ They're cheap and common animals.
→ They can be either a source of meat, skin (leather) or milk.
→ Farmers benefit a lot with them, since what they produce are things of everyday consumption.
→ You don't need to spend much to be able to have them (mostly only with land).
Hope it helped,
BioTeacher101
Meristematic , ground tissue, dermal tissue and vascular tissue .
A parasite could determine the size of the population. Whether it grows or shrinks. It could also change genetics
