Question

Which of the following lacks respiratory pigment in blood?
A)Earthworm
B)Cockroach
C)Rat
D)All of the above

Answer 1

Hint: The insect is characterized by a flat oval body. They have a long thread-like antenna and also have a shining Black or brown leathery integument. They are also considered the most primitive living winged insect. The head is generally bent downwards and their mouthparts present at the backward instead of forward and downward.

Complete answer:
-Hemoglobin is a respiratory pigment found in humans and other vertebrates. Its function is to increase the oxygen-carrying capacity of the blood.
-Hemoglobin, hemocyanin, hemerythrin, and chlorocruorin are the four most common respiratory pigments found in the vertebrates.
-The circulatory media in the cockroach is known as hemolymph. It comprises colorless plasma and many corpuscles called hemocytes.
-So, no respiratory pigments are found in the cockroach body. Therefore in the cockroach body, there is no transport of respiratory gases.
-The function of hemolymph is to transport various nutrients from one part of the body to the other part of the body. It also helps to carry nitrogenous waste substances from the tissue to the organ of excretion.

Additional Information:
Cockroaches mostly found in damp but warm places. Cockroaches are found in places where large quantities of food are available like in kitchens, hotels, bakeries, restaurants, warehouses. It can also be seen in the public latrines.
-Cockroaches are nocturnal insects which means they hide in the holes during the day and come out at night to feed on human food.
-Earthworms - these are an important part of the soil macrofauna, where they perform burrowing activities which in turn affect the growth of the plant and enhance the development of seedling.
-Rats - these are the medium size rodents found in Asia and Australia but now they are found all over the world. They are well-known carriers of diseases.
So, the correct answer is “Cockroach”.

Note: -The hemolymph is generally colorless because no blood cells or respiratory pigments are present in them. Therefore cockroaches lack respiratory pigment.
-Cockroaches lack hemoglobin in their blood so their body comprises white blood.