Question

Which of the following is non poisonous?
A. Scorpion
B. Centipede
C. Crab
D. Spider

Answer 1

Poisonous insects also used as a medicine. The poisons are used for malaria, typhoid, chest pain and ulcer. Insects affect the human body either directly or indirectly. In a direct way the insects bite and sting the human. In an indirect way humans are affected by eating the poisoned food which is affected by the insects. It also transmits the disease to humans and plants. These types of insects not only affect humans but also the plant's growth.

Complete answer:
Option A Scorpion: Scorpion's venom is the mix of neurotoxin. It affects the nerve system of the human body. Stings by Scorpio can cause cardiac arrest, death and breathing difficulties. Leiurus quinquestriatus is the killing type of scorpion in the earth. So it is called as a death stalker scorpion. It produces two milligrams of venom at the time.
Option A is the incorrect answer.
Option B Centipede: Centipede uses their venom to kill their prey. It bites humans rarely. Its toxin contains the histamine, serotonin, and cardio-depressant toxin-S. The venom contains a pharmacologic combination of toxins. It produces serious effects in the human body such as neurotoxicity, cardiac anaphylaxis.
Option B is the incorrect answer.
Option C Crab: Crab has no mechanism for delivering the toxins or poisons. If the human touches or attacks the crab then only it will bite. So poisoning occurs only when humans consume the crab. Saxitoxin and tetrodotoxin are the poisonous material in the crab. It is in their egg mass and crab muscles of crab.
Option C is the correct answer.
Option D: Spider' venom produced by the bite. Many spiders are not poisonous but the black widow and brown recluse are the poisonous spiders in the earth. These generally live in the sheds and don’t bite the humans unless threatening. The spider effect occurs suddenly or lately. Symptoms for the spider bite are redness on the skin and swelling. Anti venom is also helpful to cure the disease.
Option D is the incorrect answer.

Option C is the correct answer.

Note:
Some of the crabs are also used for eating purposes. Some of the Xanthidae family crabs are poisonous to eat. Crab lungs are poisonous because they taste terrible and hard to digest. If the lungs of crabs like feathery coin lining then it has a small amount of poison. Centipede venom is used to treat tetanus and tuberculosis. Spider venom is called latrodectism. Venom of scorpion is used to remove the tumor in the brain and also to treat cancer cells by acting as the chlorotoxin.