Assertion : Blood in cockroach is colourless haemolymph with no respiratory pigment. Reason : Respiration in cockroach occurs through diffusion in haemolymph.

Step-by-step solution

The colourless blood or haemolymph of cockroach has a clear plasma and numerous white corpuscles called haemocytes. Being devoid of any respiratory pigment, it does not serve for gaseous exchange. Its plasma contains about 70 % water. Rest of it is composed of amino acids, uric acid, proteins, sugars, fats, and salts of sodium, potassium, calcium and magnesium. Transportation of these materials between different parts of body is the main function of haemolymph. In all terrestrial insects, like cockroach, every tiss