A) birds
B) reptiles
C) mammals
D) amphibians
Correct Answer: C
Solution :
Blood platelets are present in blood of Mammals only. They are also known as thrombocytes. They are non-nucleated, round or oval, biconvex, disc-like bodies. They are formed by the fragmentation of cells called ?Megakaryocytes? from bone marrow. Their number varies from 2 to 5 lacs per \[c{{m}^{3}}\] of blood. Their 50% part is protein and 15% fats. Protein mainly includes a contractile protein thrombosthenin. Their lifespan is one week only. They are the source of thromboplastin and play major role in blood clotting. In birds, heart is 4 chambered. Sinus venosus is absent and renal portal system is very much reduced. Red blood cells are nucleated, oval and biconvex. In Reptiles, heart consists of left and right auricle and a imperfectly divided ventricle. RBCs are oval and nucleated. Amphibians blood contains large oval nucleated RBCs and haemoglobin serves as respiratory pigment.
You need to login to perform this action.
You will be redirected in
3 sec
