Question

Match the animals listed in column I with their nature of blood listed in column II. Choose the answer which gives the correct combination of the alphabets of the two columns.

Column I	Column II
A.Man	1.Plasma and cells are colourless
B.Earthworm	2.Plasma is colourless and nucleated RBCs
C.Cockroach	3.Plasma is colourless and enculeated RBCs
D. Frog	4.Plasma is red and nucleated, colourless RBCs
	5.Plasma and RBCs have haemoglobin

(a)A-1, B-4, C-2, D-3
(b)A-5, B-3, C-1, D-4
(c)A-3, B-4, C-1, D-2
(d)A-4, B-5, C-3, D-2

Answer 1

Hint The nature of blood may be different for different animals but perform the same function. Blood transports oxygen and nutrients to all the body parts and carries carbon dioxide and other waste materials to the lungs, kidneys, and digestive system so that they can be removed from the body.

Complete answer:
-About 55% of blood in humans is composed of plasma. It is a fluid that serves as the blood's liquid medium and is straw-yellow in colour. The main features of red blood cells include biconcave circular structure and are enucleated.
-Blood is reddish in colour in earthworms. It is formed of plasma and corpuscles (corpuscles are amoeboid, colourless and nucleated). The plasma also contains a red pigment known as haemoglobin.
-As cockroaches lack haemoglobin in their blood, therefore they have white blood. Haemoglobin which is primarily made up of iron is the pigment that gives human blood its red colour. Cockroaches have an open circulatory system and body cavities filled with the haemolymph.
-Frog blood is basically similar to human blood in structure. Like human blood, frog blood has liquid plasma matrix and red blood cells. But unlike the red blood cells of humans which are enucleated, the mature red blood cells of frogs have nuclei. Frogs have white blood cells with no platelets.

Additional information:
Mammalian erythrocytes or red blood cells circulate in the body without a nucleus. During the developmental stage in the bone marrow, erythroid progenitors expand, mature and condense and expel their nucleus. According to an estimate, it occurs 2 million/second in a healthy adult human. The processes that regulate this function are extremely poorly defined. Interestingly, enucleation is strictly restricted to mammals. All mammals possess nucleated red blood cells whereas, on the other side erythrocytes of birds, reptiles, amphibians and fish all possess their nuclei.

So, the correct answer is 'A - 3, B - 4, C - 1, D - 2'.

Notes: Red blood cells are enucleated so that they have a larger surface area for the binding of oxygen to proteins. The lack of a nucleus causes what is known as the biconcave hollow, which is the typical shape of the red blood cell.