Deletions occur when a chromosome breaks and some genetic material is lost. Deletions can be large or small, and can occur anywhere along a chromosome.
The best answer is organisms...
Cells only grow to replace other cells that die off and allow for the continued existence of the organism.
Please correct me if I'm wrong... :)
Perch have paired pectoral and pelvic fins, and two dorsal fins, the first one spiny and the second soft. These two fins can be separate or joined.
The answer is competition
Cancer, disease, birth defects.
