If the head of cockroach is removed, it may live for few days because :
1. the supra-oesophageal ganglia of the cockroach are situated in ventral part of abdomen.
2. the cockroach does not have nervous system.
3. the head holds a small proportion of a nervous system while the rest is situated along the ventral part of its body.
4. the head holds a \(1/3^{rd}\) of a nervous system while the rest is situated along the dorsal part of its body.