Which of the following is a characteristic feature of the phylum Porifera? MCQ with Answer and Explanation

Explanation:
The nervous system is divided into the central nervous system (CNS) and the peripheral nervous system (PNS). The CNS consists of the brain and the spinal cord, which process and coordinate information. The PNS consists of all the neural structures outside the CNS, including cranial nerves, spinal nerves, and ganglia, which connect the CNS to the rest of the body. Thus, statements 1 and 3 are correct.

Explanation:
Dengue is a viral disease caused by the Dengue virus, not a protozoan (malaria is caused by a protozoan). Filariasis (elephantiasis) is caused by parasitic nematode worms like Wuchereria bancrofti, which block lymphatic vessels. Pneumonia is an infection that inflames the air sacs in one or both lungs, affecting the respiratory system. Thus, statements 2 and 3 are correct.

Explanation:
Trypsinogen is an inactive proenzyme secreted by the pancreatic acinar cells. Upon entering the small intestine (duodenum), it is specifically activated into the active enzyme trypsin by the enzyme enterokinase (also known as enteropeptidase), which is secreted by the intestinal mucosa. Trypsin then activates other pancreatic proenzymes like chymotrypsinogen and procarboxypeptidase. Pepsinogen is activated by HCl.